How to Program in CPP / C++ and C in Linux

Array and Pointers in C FAQ in Interviews 2014

2014-01-08T21:04:00.003+05:30

http://clinuxcode.blogspot.in/ http://lealmitra.blogspot.in/ http://codefora.blogspot.in/

How to prepare C++/CPP/C for interview

2013-05-11T11:23:00.003+05:30

Frequently asked C++ questions in interviews:

How to compare two strings using pointer without strcmp

2013-05-09T21:30:00.001+05:30

/*C++/CPP/C program to compare two strings without using library function strcmp*/

#include<stdio.h>

#include<string.h>

int strCmp(char *p1, char *p2);

int main()

{

char arr1[20];

printf("Enter a String:\n");

scanf("%s",&arr1);

char arr2[20];

printf("Enter a String:\n");

scanf("%s",&arr2);

printf("You entered:%s and %s\n",arr1,arr2);

int result;

result=strCmp(arr1, arr2);

if(result==0)

printf("Equal\n");

else

printf("Not Equal.\n");

return 0;

}

int strCmp(char *p1, char *p2)

{

while(*p1++==*p2++)

{

if(*p1=='\0'|| *p2=='\0')

{

break;

}

}//end of while

if(*p1=='\0' && *p2=='\0')

{

return 0;

}

else

{

printf("else\n");

return -1;

}

* $ gcc strCmp.c

$ ./a.out

Enter a String:

India

Enter a String:

Indi

You entered:India and Indi

else

Not Equal.

$ ./a.out

Enter a String:

Indi

Enter a String:

India

You entered:Indi and India

else

Not Equal.

$ ./a.out

Enter a String:

India

Enter a String:

India

You entered:India and India

Equal

Previous Home Next

How to copy a string without using strcp with pointer

2013-05-05T23:17:00.002+05:30

/*How to copy a string without using library function strcpy.
How to use pointer/array to copy a string/sentence. C++/CPP/C program/code to copy a string/word/sentence without using inbuilt function strcpy.How copy a string without using library function strlen. cpp program to copy a string using pointer.cpp program to copy a string without using library function strcpy*/

#include<stdio.h>

#include<string.h>

void strCpy(char *p2,char *p1);

int main()

{

char arr1[20];

char arr2[20];

printf("Enter a String:\n");

scanf("%s",&arr1);

strCpy(arr2, arr1);

printf("You entered and copied:%s\n",arr2);

return 0;

}

void strCpy(char *p2,char *p1)

{

while(*p1!='\0')

{

*p2++=*p1++;

}

*p2='\0';

}

* Enter a String:

India

You entered and copied:India

/*cpp program for copying a string without using library function strcpy*/

#include<stdio.h>

#include<string.h>

int main()

{

char arr1[20];

printf("Enter a String:\n");

scanf("%s",&arr1);

char arr2[20];

int i,j;

for(i=0,j=0;arr1[i]!=0;i++,j++)

{

arr2[j]=arr1[i];

}

arr2[j]='\0';

printf("You entered and copied:%s\n",arr2);

return 0;

}

Enter a String:

Hello

You entered and copied:Hello

Previous Home Next

How to find the length of a string without using library function strlen

2013-05-04T19:32:00.000+05:30

/*How to find length of a string without using library function strstr.
How to use pointer/array to find length of string sentence. C++/CPP/C program/code to find length a string/word/sentence without using inbuilt function strlen.How to find the length of a string without using library function strlen*/

#include<stdio.h>

#include<string.h>

int strLen(char *p);

int main()

{

char arr1[20];

printf("Enter a String:\n");

scanf("%s",&arr1);

printf("You entered:%s\n",arr1);

int n;

n=strLen(arr1);

printf("Strlen of entered string is:%d\n",n);

return 0;

}

int length=0;

int strLen(char *p)

{

printf("Inside strLen\n");

char *temp;

temp=p;

while(*temp)

{

temp++;

}

return (temp-p);

}

Enter a String:

India

You entered:India

Inside strLen

Strlen of entered string is:5

* */

Previous Home Next

How to reverse a string using pointer or array in cpp without using strrev library function

2013-05-03T07:30:00.001+05:30

How to reverse a string using pointer or array. CPP program for reversing a strings without using inbuilt library function strrev. How to reverse a sentence in cpp/C++/C without using library function strrev.Program to reverse a string using pointer.
#include<stdio.h>
#include<string.h>
int main()
{
char arr1[20];
printf("Enter a String:\n");
scanf("%s",&arr1);
printf("You entered:%s\n",arr1);

char arr2[20];

char *p1=arr1+strlen(arr1)-1;
char *p2=arr2;
while(p2<p1)
{
*p2++=*p1--;
}
printf("You entered:%s\n",arr2);
return 0;
}
/*OUTPUT

* Enter a String:
India
You entered:India
You entered:aidnI
*/

/*How to reverse a string without using library function strrev and strlen*/
#include<stdio.h>
#include<string.h>

void strRev(char *arr1);

int main()
{
char arr1[20];
printf("Enter a String:\n");
scanf("%s",&arr1);
printf("You entered:%s\n",arr1);

strRev(arr1);

return 0;
}
void strRev(char *arr1)
{
char *p1=arr1+strlen(arr1)-1;
char arr2[20];
char *p2=arr2;

while(p2<p1)
{
*p2++=*p1--;
}
*p2='\0';

printf("Reverse String is:%s\n",arr2);
}

/*
Enter a String:
India
You entered:India
You entered:aidnI
*/

Previous Home Next

CPP program for concatenating two strings without using inbuilt library function strcat

2013-04-28T20:30:00.002+05:30

How to concatenate two strings using pointer or array. CPP program for concatenating two strings without using inbuilt library function strcat. How to concatenate two strings in cpp/C++/C without using inbuilt in function strcat.Program to concatenate two strings using pointer.

#include<stdio.h>
#include<string.h>
int main()
{
char arr1[20];
printf("Enter a String:\n");
scanf("%s",&arr1);

char arr2[20];
scanf("%s",&arr2);

printf("You entered:%s and %s\n",arr1,arr2);

int i=0,j=0,length=0;

for(i=0;arr1[i]!='\0';i++)
{
    length++;
}

for(i=length,j=0;arr2[j]!='\0';i++,j++)
{
    arr1[i]=arr2[j];
}
arr1[i]='\0';

printf("Concated string is:%s",arr1);
    return 0;
}
/*
Enter a String:
Hello
India
You entered:Hello and India
Concated string is:HelloIndia
*/

Previous Home Next

How to search a substring in C++/Cpp without using library function strstr

2013-04-26T23:06:00.000+05:30

/*How to search a sub string without using library function strstr.
How to use pointer/array to search substring in a string sentence.

C++/CPP/C program/code to search a word in a sentence without using inbuilt function strstr*/

#include<stdio.h>

#include<string.h>

int main()

{

char arr1[50];

printf("Enter a String:\n");

scanf("%s",&arr1);

char arr2[20];

printf("Enter a String:\n");

scanf("%s",&arr2);

printf("Searching for:%s\n",arr2);

int count1, count2;

count1=0; count2=0;

while(arr1[count1]!='\0')

count1++;

while(arr2[count2]!='\0')

count2++;

int i,j,flag;

for(i=0;i<count1-count2;i++)

{

for(j=i;j<i+count2;j++)

{

flag=1;

if(arr1[j]!=arr2[j-i])

{

flag=0;

break;

}

if (flag==1)

break;

}

if (flag==1)

printf("yes found\n");

else

printf("Not found\n");

return 0;

}/*

Enter a String:

zxcvbnaaaSONYdkjsdfklj

Enter a String:

SONY

Searching for:SONY

yes found*/

Previous Home Next

How to use make file in CPP C+++ C

2013-04-25T08:09:00.001+05:30

/*What is makefile ?
---------------------------------------
makefile is a script/utility that contains target, dependencies and actions to compile modified file/files in a project of multple files. */

/*SYNTAX
-----------------------------------
target:dependencies
[tab] actions
.
.

*/

/*HOW To USE MAKEFILE in Cpp
---------------------------------------
steps to execut:

make -f newmakefile
newmakefile //generating .o
newmakefile //generating executable target_bin
target_bin //execute target_bin
*/

//makefile
//-----------------------------------------------
all:main.o module.o
    gcc main.o module.o -o target_bin
main.o:main.c module.h
    gcc -I . -c main.c
module.o:module.c module.h
    gcc -I . -c module.c

//module.c contailns definition of the function1
//---------------------------------------------------
#include "module.h"

void function1()
{
    printf("\nHeloo function from Makefile\n");
}

//module.h contains the headers and declaraion of function1
//---------------------------------------------------
#include<stdio.h>
void function1();

//main.c contains the call to the function1
//---------------------------------------------------
//stdio.h not needed as included in module.h
#include "module.h"
int main()
{
    function1();
    return 0;
}

//I . specifies to look header files in current direcory
//all: is a special target that take object files as depenedencies
//main.o: is filename target whose dependency is src file
//clean: is a special target that takes no dependency.
//        rm -rf   *.o
//        rm target_bin
//makefile first compiles the files with no dependency then
//file which has dependency of compiled files and so on

Previous Home Next

How to implement msgq message queue in CPP C C++

2013-04-22T22:13:00.003+05:30

//Program to implement msgq

/*CPP Program for msg queue in Linux

pipes work with related process parent-child only.

Fifo can make unrelated process to communicate but

fifo created does not persists for use in future.

Shared memory is similar to fifo but over comes this and can be used later also.

Program to implement IPC Message Queues IPC mechanism.

msgqSendkirk.c adds the message on the message queue.

msgqRecvSpock.c reads and removes the message from the message

queue.To use this program first compile and run msgqSendkirk.c

to add a message to the message queue. To see the

Message Queue in other terminal run msgqRecvSpock.c

ipcs -q shows the msg ques.

ipcrm -q 131073 removes the msgq created say 131071 */

#include <stdio.h>
#include <stdlib.h>

#include <errno.h>

#include <string.h>

#include <sys/types.h>

#include <sys/ipc.h>

#include <sys/msg.h>

//1. declaring the msg structure

struct my_msgbuf

{

long mtype;

char mtext[200];

};

int main(void)

{

struct my_msgbuf buf;

int msqid;

key_t key;

//2. creating key with ftok

key = ftok("msgqSendkirk.c", 'B');

///local/kumarsah/comp/linuxdemo/msgqSendkirk.c

//3. creating msgq with msgget

msqid = msgget(key, 0644 | IPC_CREAT);

printf("Enter lines of text, ^D to quit:\n");

buf.mtype = 1;

//4. type and send the message

while(fgets(buf.mtext, sizeof buf.mtext, stdin) != NULL)

{

int len = strlen(buf.mtext);

msgsnd(msqid, &buf, len+1, 0);

}

//5. removing msgq with msgctl with IPC_RMID

msgctl(msqid, IPC_RMID, NULL) ;

return 0;

}

// msgqRecvSpock.c

#include <stdio.h>

#include <stdlib.h>

#include <errno.h>

#include <sys/types.h>

#include <sys/ipc.h>

#include <sys/msg.h>

struct my_msgbuf {

long mtype;

char mtext[200];

};

int main(void)

{

struct my_msgbuf buf;

int msqid;

key_t key;

if ((key = ftok("msgqSendkirk.c", 'B')) == -1) {/* same key as msgqSendkirk.c */

perror("ftok");

exit(1);

}

if ((msqid = msgget(key, 0644)) == -1) { /* connect to the queue */

perror("msgget");

exit(1);

}

printf("spock: ready to receive messages:\n");

for(;;) { /* Spock never quits! */

if (msgrcv(msqid, &buf, sizeof(buf.mtext), 0, 0) == -1) {

perror("msgrcv");

exit(1);

}

printf("spock: \"%s\"\n", buf.mtext);

}

return 0;

}

/*terminal 1:

$ gcc msgqSendkirk.c

$ ./a.out

Enter lines of text, ^D to quit:

dwqdadd

aaaaaaaaa

ddddd

ddd

terminal2:

gcc msgqRecvSpock.c

$ ./a.out

spock: ready to receive messages:.

spock: "dwqdadd"

sldjslds

spock: "aaaaaaaaa"

spock: "ddddd"

ddd

Previous Home Next

How to use callback function pointer in cpp/C/C++

2013-04-21T11:15:00.000+05:30

Program for callback /function pointer in CPP/C/C++

What is function pointers?As we know a pointer is a special variable that folds the address of another variable.
Function pointer is also a pointer that hold the address of a function.

Int array[10]; // here array is a constant pointer to a 10 element array. That is constant pointer to first element of array.

Can we declare a non-constant pointer to a function? Yes we can .

Int (*funcPtr)();//funcPtr is a pointer to a function that takes no arguments and returns an integers.//parenthesis is must here as we are not assigning the return type.

Int (*funcPtr)(int,int);//funcPtr is a pointer to a function that takes two arguments and returns an integers.

Callback function-callback function is reference to a piece of executable code that is past as arguments to another code.

This allows a lower level layer code to call a function defined in higher level layer.
Function pointer are used in many situation like if you are writing a code for sorting an array but instead of hard coding the code of comparison of elements to sort we can provide a way to the user to defined how a particular part of the code will be performed such as array is sorted in ascending or descending order.

Simple example of a function:

#include<stdio.h>
int func(int,int);
int main()
{
int sum;

sum=func(1,2);

printf("\sum=%d\n",sum);

return 0;

}

int func(int a, int b)

{

return a+b;

}

Callback function : example of a function pointer in cpp/C/C++:

//Program for callback function Pointer

#include<stdio.h>

int func(int,int);

int main()

{

//decalring a func ptr taking 2 args and returning a int

int(*funcPtr)(int, int);

int sum;

funcPtr=func;//assiging a function addr to ptr

//calling function through explicit dereference

sum=(*funcPtr)(1,2);

printf("\nSum=%d\n",sum);

//calling function through implicit dereference

sum=funcPtr(1,2);

printf("\nSum=%d\n",sum);

return 0;

}

int func(int a, int b)

{

return a+b;

}

Simples Way to learn Data Structure in C++ CPP or C
C++ Program for Circular Queue implementation using linked list

C++ program for Circular Queue implementation using Array

C++ program for reversing single Linked list nodes

C++ Program for sorted single linked list with class

C++ Program for BST-Binary Search Tree

Previous Home Next

How to use malloc for 2d array dynamic memory allocation

2013-04-13T19:30:00.002+05:30

/*How to use malloc for 2d array dynamic memory allocation. How to write 2-d array with dynamic memory allocation */

#include<stdio.h>

#include<malloc.h>

int main()

{

int r,c,i,j;

printf("Enter No of rows and columns:");

scanf("%d%d",&r,&c);

int **array;

array=(int**)malloc(r*sizeof(int));

for(i=0;i<r;i++)

{

array[i]=malloc(c*sizeof(int));

}

printf("\n Enter the elements 1 by 1:\n");

for(i=0;i<r;i++)

{

for(j=0;j<c;j++)

{

scanf("%d",&array[i][j]);

}

// printf("\t");

}

printf("You Entered:\n");

for(i=0;i<r;i++)

{

for(j=0;j<c;j++)

{

printf("%d",array[i][j]);

printf("\t");

}

printf("\n");

}

printf("\n");

}

* $ ./a.out

Enter No of rows and columns:4

Enter the elements 1 by 1:

You Entered:

1 2 3 4

5 6 7 8

8 8 8 8

1 1 1 1

Dynamic memory allocation for multi dimensional array here for 2-d ( two dimensional array).There are various ways to allocate memory dynamically for multi dimensional array:

1. Pointer to pointer

First memory is allocated for array which contains pointers to array to integers.

Then, memory is allocated for the each array pointed by the pointers.

Finally memory is de-allocated in the reverse order of the allocation.

Actually we allocate memory for number of rows and then columns.

1	2	3
4	5	6
7	8	9
10	11	12
13	14	15

It can be done by pointer to pinter to int.
example as above.

Int **array; //array is a pointer to pointer to int.

Array is a pointer to pointer to int. it means that array first points to pointers then in turn pointers point to integers. We need to allocate enough memory for the pointers to hold ponters to integers which nothing but memory for the rows. So dynamic memorty allocation for 2d array would be like this.

Previous Home Next

How to use new to allocate memory for 3d array in CPP C++

2013-04-13T19:26:00.000+05:30

/*How to use new to allocate memory for 3d array. How to use malloc for 3 dimensional array. CPP program for dynamically allocating memory for 3d array. How to write three dimensional array with malloc with new */

#include<iostream>

using namespace std;

int main()

{

// 3 Dimensions Array

// two 3x4 array

int x = 2, y = 3, z = 4;

int i, j, k;

// memory allocation for 3D

int ***array3D = new int**[x];

for(i = 0; i < x; i++)

{

array3D[i] = new int*[y];

for(j = 0; j < y; j++)

{

array3D[i][j] = new int[z];

}

// Accessing 3d array elements

for(i = 0; i < x; i++)

{

cout << i << endl;

for(j = 0; j < y; j++)

{

cout << endl;

for(k = 0; k < z; k++)

{

array3D[i][j][k] = (i * y * z) + (j * z) + k;

cout << '\t' << array3D[i][j][k];

}

cout << endl << endl;

}

// deleting 3d array

for(i = 0; i < x; i++)

{

for(j = 0; j < y; j++)

{

delete[] array3D[i][j];

}

delete[] array3D[i];

}

delete[] array3D;

return 0;

}

/*OP:

0 1 2 3

4 5 6 7

8 9 10 11

12 13 14 15

16 17 18 19

20 21 22 23

Previous Home Next

How to learn stack and flow of function call and control in cpp

2013-04-11T16:01:00.003+05:30

/*How to learn stack. Stack is memory in which Last in first out is followed.
When function call is encountered the address of the next statement is stored or pushed in the stack. When the control returns back from the definition to calling function the address is poped out which is nothing but the statement next to the function call and executed.*/
#include<stdio.h>
#include<iostream>
using namespace std;
void function1();
void function2();

int main()
{
printf("1\n");
printf("2\n");
function1();
printf("3\n");
printf("4\n");

return 0;
}
void function1()
{
printf("1.1\n");
printf("1.2\n");
function2();
printf("1.3\n");
printf("1.4\n");
}
void function2()
{
printf("2.1\n");
printf("2.2\n");
}

/*
1
2
1.1
1.2
2.1
2.2
1.3
1.4
3
4
*/
/*
First 1 and 2 gets printed then function1 gets called and address of 3 gets stored instack.Now in inside function1 1.1 and 1.2 gets printed and function2 gets called and address of 1.3 gets stored in stack. Now inside function2 2.1 and 2.2 gets printed. Then as stack is LIFO so the last address ie of 1.3 was stored in stack so 1.3 followed by 1.4 is printed. Before the address of 1.3 address of 3 was stored in stack so now 3 and the next statement 4 gets printed
*/

Previous Home Next

How to learn recursive function call in cpp/C++/C

2013-04-11T15:57:00.003+05:30

/*How to learn recursive function call in cpp/C++/C
Cpp Program to learn recursive function */
#include<iostream>
using namespace std;
int sum(int m, int k);
int main()
{
int i,m,k;
m=3;
k=2;
i=sum(m,k);
cout<<"sum="<<i<<endl;
//return 0;
}
int sum(int rm, int rk)
{
cout<<rm<<" "<<rk<<endl;
if(rm==0) return(rk);//termination condition
else return(1+sum(rk, rm-1));//recursive condition//if not +1 then sum=0
}

/*
3 2
2 2
2 1
1 1
1 0
0 0
sum=5 //in stack first address of sum(3,2) was stored
*/

Previous Home Next

How to distinguish between call by value, call by reference, call by address

2013-04-11T14:14:00.001+05:30

/*How to distinguish between call by value, call by reference, call by address.
Program to distinguish between pass by value,pass by reference,pass by address. Call by reference and call by address affects the calling value while call by value doe not. Most important difference is that in call by value new object is created which is some times such as when size of the variable is too large is not desirable so call by reference is preferred over call by value*/

#include<stdio.h>
#include<iostream>
using namespace std;
void callbyreference(int * x);//pass by address
int main()
{
int x;
x=10;
printf("Before x=%d",x);//10
callbyvalue(&x);
printf("\nAfter x=%d",x);//15
printf("\n");
return 0;
}

void callbyreference(int * x)
{
*x=*x+5;//mind the*
}

//CALL BY REFERNCE, PASS BY REFERNCE
/*

void callbyrefernce(int & x);
int main()
{
int x;
x=10;
printf("Before x=%d",x);//10
callbyrefernce(x);//pass by refernce
printf("\nAfter x=%d",x);//15
printf("\n");
return 0;
}

void callbyvalue(int & x)
{
x=x+5;
}
*/

//CALL BY VALUE, PASS BY VALUE
/*
void callbyvalue(int x);
int main()
{
int x;
x=10;
printf("Before x=%d",x);//10
callbyvalue(x);//pass by value
printf("\nAfter x=%d",x);//10
printf("\n");
return 0;
}

void callbyvalue(int x)
{
x=x+5;
}
*/

Previous Home Next

How to write cpp program for Circular Queue using Array

2013-03-30T20:15:00.000+05:30

How to write C++ program for Circular Queue using Array

C++ program to implement Circular Queue using Array

Circular Queue implementation using Array
CPP program for implementing Circular Queue using Array

#include<iostream>

using namespace std;

#define MAXSIZE 4

class queue

{

private:

int cq[MAXSIZE];

int front, rear;

public:

queue()

{

int cq[MAXSIZE]={0};//error: array must be initialized with a brace-enclosed initializer

front= -1;

rear = -1;

}

void insert(int item)

{

cout<<"\n in insert.\t";

if( ( (front==0)&&(rear==MAXSIZE-1)%MAXSIZE ) || front==(rear+1)%MAXSIZE )

{

cout<<"Q is full.\n";

}

else

{

if(front==-1)

front=rear=0;

else

rear=(rear+1)%MAXSIZE;

cq[rear]=item;

cout<<"\n front = "<<front<<" rear = "<<rear<<endl;

}

void display()

{

int i;

for(i=0;i<MAXSIZE;i++)

{

cout<<cq[i]<<" ";

}

cout<<endl;

}

void deletee()

{

if(front==-1)

{

cout<<"Q is empty.\n";

}

else

{

int temp;

temp=cq[front];

cq[front]=0;

if(front==rear)//only 1 elt was there

front=rear=-1;//delete the single so q is empty

else

front=(front+1)%MAXSIZE;//if more than 1 elt then delete frm front

cout<<"\n Deleted elt is:"<<temp<<endl;

cout<<"\n front = "<<front<<" rear = "<<rear<<endl;

}

};

int main()

{

queue q;

q.insert(10);

q.insert(20);

q.insert(30);

q.insert(40);

q.display();

q.insert(111);//Q is full so make same place by deleting fronts

q.display();

q.deletee();

q.display();

q.insert(100);

q.display();

return 0;

}

in insert.

front = 0 rear = 0

in insert.

front = 0 rear = 1

in insert.

front = 0 rear = 2

in insert.

front = 0 rear = 3

10 20 30 40

in insert. Q is full.

10 20 30 40

Deleted elt is 10.

front = 1 rear = 3

0 20 30 40

in insert.

front = 1 rear = 0

100 20 30 40

*/
Simples Way to learn Data Structure in C++ CPP or C

C++ Program for sorted single linked list with class

C++ Program for BST-Binary Search Tree

C++ Program for Circular Queue implementation using linked list

C++ program for Circular Queue implementation using Array

C++ program for reversing single Linked list nodes

C++ Program for sorted single linked list with class

C++ Program for BST-Binary Search Tree

Previous Home Next

How to write cpp program for Circular Queue using Linked List

2013-03-30T20:09:00.001+05:30

/*C++ Program for Circular Queue implementation using linked list

Cpp program to implement Circular Queue using Linked List*/
C++ Program for implementing Circular Queue with Linked List

#include<iostream>

using namespace std;

class queue

{

private:

struct node

{

int data;

node* link;

};

node *front;

node *rear;

public:

void insert(int);

void display();

void del();

queue()

{

front=NULL;

}

};

void queue::insert(int d)

{

//cout<<"insert called\n";

node *newnode=new node;

newnode->data=d;

newnode->link=NULL;

if(front==NULL)

{

front=rear=newnode;

}

else

{

rear->link=newnode;

rear=newnode;

}

void queue::display()

{

if(front==NULL){cout<<"Queue is empty.\n";}

else

{

node *ptr;

ptr=front;

while(ptr)

{

cout<<ptr->data<<" ";

ptr=ptr->link;

}

cout<<endl;

}

void queue::del()

{

node* temp;

temp=front;

if(front==NULL){cout<<"Queue is Empty.\n";}

else

{

node* temp;

temp=front;

front=front->link;

//rear->link=front;

delete temp;

}

int main()

{

queue q;

q.insert(10);

q.insert(20);

q.insert(100);

q.insert(40);

q.insert(300);

q.display();

q.del();

q.display();

return 0;

}

10 20 100 40 300

20 100 40 300

Simples Way to learn Data Structure in C++ CPP or C

C++ Program for sorted single linked list with class

C++ Program for BST-Binary Search Tree

C++ Program for Circular Queue implementation using linked list

C++ program for Circular Queue implementation using Array

C++ program for reversing single Linked list nodes

Previous Home Next

How to write cpp program for BST Binary Search Tree

2013-03-30T20:04:00.000+05:30

/*BST-Binary Search Tree Program for insertion and traversal
How to write C++ Program for BST-Binary Search Tree
Cpp program for BST Binary Search Tree implementation with class*/

-->

//bst-Binary Search tree

#include<iostream>

using namespace std;

class BST

{

private:

struct node

{

int data;

node *left;

node *right;

};

node* start;

public:

BST(){start=NULL;}

void insert(int data);

void traverse();

void inorder(node *);

void preorder(node *);

void postorder(node *);

};

void BST:: insert(int d)

{

node *newnode;

newnode=new node;

newnode->data=d;

newnode->left=NULL;

newnode->right=NULL;

node *ptr;

ptr=start;

if(start==NULL)

{

start=newnode;

}

else

{

while(ptr!=NULL)

{

if(d<ptr->data)

{

if(ptr->left==NULL)

{

ptr->left=newnode;

ptr=NULL;

}

else

{

ptr=ptr->left;

}

else

{

//if(d>ptr->data)

//{

if(ptr->right==NULL)

{

ptr->right=newnode;

ptr=NULL;

}

else

{

ptr=ptr->right;

}

// }

}

void BST::traverse()

{

cout<<"\n Inorder:\n";

inorder(start);

cout<<"\n Preorder:\n";

preorder(start);

cout<<"\n Postorder:\n";

postorder(start);

}

void BST::inorder(node *ptr)

{

if(ptr!=NULL)

{

inorder(ptr->left);

cout<<ptr->data<<"\t";

inorder(ptr->right);

}

void BST::preorder(node *ptr)

{

if(ptr!=NULL)

{

cout<<ptr->data<<"\t";

preorder(ptr->left);

preorder(ptr->right);

}

void BST::postorder(node *ptr)

{

if(ptr!=NULL)

{

postorder(ptr->left);

postorder(ptr->right);

cout<<ptr->data<<"\t";

}

int main()

{

BST b;

b.insert(8);

b.insert(3);

b.insert(10);

b.insert(1);

b.insert(6);

b.insert(7);

b.insert(4);

b.insert(10);

b.insert(14);

b.insert(13);

b.traverse();

return 0;

}

$ g++ bst_revision.cxx

$ ./a.out

Inorder:

1 3 4 6 7 8 10 10 13 14

Preorder:

8 3 1 6 4 7 10 10 14 13

Postorder:

1 4 7 6 3 13 14 10 10 8

Depth-first

Pre-order traversal sequence: F, B, A, D, C, E, G, I, H (root, left, right)
In-order traversal sequence: A, B, C, D, E, F, G, H ,I (left, root, right)
Post-order traversal sequence: A, C, E, D, B, H, I, G, F (left, right, root)

Breadth-first

Level-order traversal sequence: F, B, G, A, D, I, C, E, H

Inorder:

1 2 3 4 5 6 7 8 9

Pre order:

6 2 14 3 5 7 9 8

Post order:

1 3 5 4 2 8 9 7 6
Simples Way to learn Data Structure in C++ CPP or C

C++ Program for Circular Queue implementation using linked list

C++ program for Circular Queue implementation using Array

C++ program for reversing single Linked list nodes

C++ Program for sorted single linked list with class

C++ Program for BST-Binary Search Tree

Previous Home Next

How to write cpp program to reverse a linked list

2013-03-30T19:57:00.001+05:30

//C++ program for reversing single Linked list nodes
Cpp program for implement reversing Single Linked List
Single linked list program for reversing the nodes
How to reverse linked list

#include<iostream>

using namespace std;

struct node

{

node *next;

int data;

};

class ll

{

private:

node *start;

public:

ll(){start=NULL;}

void insert(int a)

{

cout<<"Inside Insert."<<endl;

node *newnode=new node;

newnode->data=a;

newnode->next=start;

start=newnode;

//return;

}

void display();

void del();

void reverse();

};

//void ll::insert(int a){data=a;}

void ll::display()

{

cout<<"Inside display."<<endl;

node *curr=new node;

curr=start;

while(curr!=NULL)

{

cout<<curr->data<<" ";

curr=curr->next;

}

cout<<endl;

}

void ll::del()

{

cout<<"Inside del."<<endl;

node *temp=new node;

temp=start;

start=start->next;

delete temp;

}

void ll::reverse()

{

cout<<"Inside reverse."<<endl;

node *next=new node; next=NULL;

node *result=new node; result=NULL;

node *current=new node;current=start;

while(current!=NULL)

{

next=current->next;

current->next=result;

result=current;

current=next;

}

start=result;

}

int main()

{

ll l;

l.insert(10);

l.insert(20);

l.insert(30);

l.insert(40);

l.display();

l.reverse();

l.display();

l.del();

l.display();

return 0;

}

/* Inside Insert.

Inside Insert.

Inside display.

40 30 20 10

Inside reverse.

Inside display.

10 20 30 40

Inside del.

Inside display.

20 30 40

Previous Home Next

How to write sorted linked list program in cpp with class

2013-03-30T19:42:00.002+05:30

How to write sorted linked list program in cpp with class

C++ Program for sorted single linked list with class

//sorted linked list latest

#include<iostream>

using namespace std;

struct node

{

int data;

node *next;

};

node *start=NULL;

void insert(int d)

{

node *newnode=new node;

newnode->data=d;

newnode->next=NULL;

//insert as first elt

if(start==NULL)

{

//start->next=newnode;

start=newnode;

}

//insert before first elt

if(newnode->data < start->data)

{

newnode->next=start;

start=newnode;

return;

}

//inserting at middle

node* prev; node *ptr;

for(prev=start,ptr=start->next;ptr;prev=ptr,ptr=prev->next)

{

if(newnode->data < ptr->data)

{

prev->next=newnode;

newnode->next=ptr;

return;

}

//inserting at last

if(ptr==NULL)

{

prev->next=newnode;

newnode->next=NULL;//must

return;

}

void display()

{

node *ptr=start;

while(ptr!=NULL)

{

cout<<ptr->data<<" ";

ptr=ptr->next;//must else infinite loop

}

cout<<endl;

}

void deleteNode()

{

int key;

cout<<"Enter elt to delete:"<<endl;

cin>>key;

//deleting the first node

if(key==start->data)

{

node *temp;

temp=start;

start=start->next;

delete temp;

return;

}

//deleting middle node

node *ptr; node *prev;

for(prev=start,ptr=start->next;ptr;prev=ptr,ptr=prev->next)

{

if(ptr->data==key)

{

prev->next=ptr->next;

delete ptr;

return;

}

//deleteing last elt means data not present

if(ptr==NULL)

{

cout<<"key "<<key<<" Not present in LL.\n";

return;

}

if(start==NULL)

{

cout<<"No Element to delete"<<endl;

return;

}

int main()

{

insert(10);

insert(4);

insert(8);

insert(9);

insert(6);

insert(7);

insert(25);

display();

deleteNode();

display();

deleteNode();

return 0;

}

/* Output:

$ ./a.out

4 6 7 8 9 10 25

Enter elt to delete:

100

key 100 Not present in LL.

4 6 7 8 9 10 25

Enter elt to delete:

key 9 Not present in LL.

Enter elt to delete:

Previous Home Next

How to see vtable virtual table for virtual functions in cpp

2013-03-30T19:34:00.002+05:30

Virtual table is look up table for virtual functions. It contains the function pointer to the virtual functions. Virtual table is created for each class having one or more virtual function and classes derived from that class.virtual pointer better known as vptr containing the address of vtable is created for the most base class thats why size of empty class with virtual function is equal to the size of a pointer(8 bytes for a 64 bit computer)while size of a empty class without any virtual functions is only one byte.

Command to see vtable/virtual table of a class.

Here if the name of the program is "classWithVf.cxx" so the command to see the vtable of the class is:

g++ -fdump-class-hierarchy classWithVf.cxx

#include<iostream>

using namespace std;

class M //empty class

{

public:

void f() {}

};

class A //empty class

{

public:

void f() {}

};

class B//empty class with 1 vf

{

public:

virtual void f() {}

};

class B1//class with 1 vf 1 dm

{

private:

char x1;

public:

virtual void f1() {}

};

class D : public B1

{

private:

char z;

public:

void f1() {}

};

class B2//clas without vf 1dm

{

private:

char a;

public:

void f2() {}

};

class B3

{

private:

char b31;

public:

void f3() {}

};

int main ()

{

M m;

cout<<"size of m:"<<sizeof(m)<<endl;// 1 obj with def constr

cout<<"size of M:"<<sizeof(M)<<endl;// 1

A *a=new A;

cout<<"size of a:"<<sizeof(a)<<endl;// 8 object with new so a is ptr here

cout<<"size of A:"<<sizeof(A)<<endl;// 1

B b;

cout<<"size of b:"<<sizeof(b)<<endl;// 8 empty class with vf

cout<<"size of B:"<<sizeof(B)<<endl;// 8

B1 b1;

// B1 *b1 = new B1();

cout<<"size of b1:"<<sizeof(b1)<<endl;//16 if obj by new //else if by def constr 8

cout<<"size of B1:"<<sizeof(B1)<<endl;//16 bytes

D *d = new D();

cout<<"size of d1:"<<sizeof(d)<<endl;//8

cout<<"size of D1:"<<sizeof(D)<<endl;//16

B2 b2;

cout<<"size of b2:"<<sizeof(b2)<<endl;//1//obj by def constr

cout<<"size of B2:"<<sizeof(B2)<<endl;//1

B3 *b3 = new B3;

cout<<"size of b3:"<<sizeof(b3)<<endl;//8 obj by new

cout<<"size of B3:"<<sizeof(B3)<<endl;//1

return 0;

}

* g++ -fdump-class-hierarchy classWithVf.cxx

gvim classWithVf.cxx.t01.class

Class M

size=1 align=1

base size=0 base align=1

M (0x2b9ff89feb60) 0 empty

Class A

size=1 align=1

base size=0 base align=1

A (0x2b9ff8a19070) 0 empty

Vtable for B

B::_ZTV1B: 3u entries

0 (int (*)(...))0

8 (int (*)(...))(& _ZTI1B)

16 B::f

Class B

size=8 align=8

base size=8 base align=8

B (0x2b9ff8a19150) 0 nearly-empty

vptr=((& B::_ZTV1B) + 16u)

Vtable for B1

B1::_ZTV2B1: 3u entries

0 (int (*)(...))0

8 (int (*)(...))(& _ZTI2B1)

16 B1::f1

Class B1

size=16 align=8

base size=9 base align=8

B1 (0x2b9ff8a19460) 0

vptr=((& B1::_ZTV2B1) + 16u)

Vtable for D

D::_ZTV1D: 3u entries

0 (int (*)(...))0

8 (int (*)(...))(& _ZTI1D)

16 D::f1

Class D

size=16 align=8

base size=10 base align=8

D (0x2b9ff8a19770) 0

vptr=((& D::_ZTV1D) + 16u)

B1 (0x2b9ff8a197e0) 0

primary-for D (0x2b9ff8a19770)

Class B2

size=1 align=1

base size=1 base align=1

B2 (0x2b9ff8a19a80) 0

Class B3

size=1 align=1

base size=1 base align=1

B3 (0x2b9ff8a19b60) 0

Note:

Sizeof returns +1 for \0

Strlen returns exact

Previous Home Next

Constructors in C++/Copy Constructor in CPP

2012-10-22T23:41:00.002+05:30

Constructors in C++/Copy Constructor in CPP:
What is constructor?
Constructor is a member function whose task is to initialize the object of a class and which is automatically gets called when object of that class gets created.
Why do we need constructor?
we need constructor to initialize the objects of class at the time of their creation.
What is Copy Constructor?
Copy Constructor is a constructor which gets called when an object is passed by value as argement or when an object is returnrd by value by a function or when an object is initialize by another object.
Why do we need Copy Constructor?
We need copy constructor to avoid shallow or member wise copy done by the the compy constructor provided by compiler.
for example:

Previous Home Next

How to use template in cpp

2012-10-20T15:51:00.000+05:30

How to use template in C++:
Template is mechanism in C++ to generate fanily of
generic classes and generic functions that works with
different types of data types hence eliminate duplicate
program for diffrent data types and make the program
more manageable and easier.

C++ Program for 1 argument template class

#include<iostream.h>
#include<string.h>
template <class T>
class test
{
T t;
public:
test(T x)//will work with int, float,char,string
{
t=x;
}
void show(void)
{
cout<<"t= "<<t<<endl;
}
};
//void test< T>::show(void)
//{
//cout<<"t"<<t<<endl;
//}
int main()
{
test<int>t1(10); //calls int version of test(T t)
t1.show();
test<float>t2(1.0); //calls float version of test(T t)
t2.show();
test<char>t3('m'); //calls char version of test(T t)
t3.show();
test<char *>t4("HelloTemplate"); // calls string version of test(T t)
t4.show();
return 0;
}

C++ Program for 1 argument template function

#include<iostream.h>
//using namespace std
template <class T>
void display(T a)
{
cout<<a<<endl;
}
int main()
{
display(10);
display(20.12);
display('M');
display("MamaMeaa");
return 0;

}

Previous Home Next

Why to use explicit keyword in C++

2012-10-02T14:59:00.001+05:30

//explicit keyword is used only with constructor
// which avoids conversion only it will allow to create objects
#include<iostream.h>
class sample
{
private:
int i;
public:
sample(){}
// explicit sample(int ii)
sample(int ii)
{
i=ii;
}

sample operator+(sample s)
{
sample temp;
temp.i=i+s.i;
return temp ;
}
void display()
{
cout<<i<<endl;
}
};
int main()
{
sample s1(25), s2;
s1.display();
s2=s1+25;
s2.display();

return 0;
}
//How to use explicit keyword in C++ with exaple
//How to use explicit keyword in C++ with exaple
//How to use explicit keyword in C++ with exaple
//Why to use explicit keyword in C++ with exaple
//Why to use explicit keyword in C++ with exaple

//overloading S2=S1+25;

Previous Home Next