C Programming

Decision Making

2021-09-24T20:50:00.007-07:00

Decision Making

C conditional statements allow you to make a decision, based upon the result of a condition. These statements are called Decision Making Statements or Conditional Statements.

Flow Chart of Control Statement:

Conditional Statements in C

if statement
if-else statement
Nested if-else statement
else if-statement
goto statement
switch statement
Conditional Operator

If Statement :

If statements in C is used to control the program flow based on some condition, it's used to execute some statement code block if the expression is evaluated to true. Otherwise, it will get skipped.

Following is the syntax of if statements:

if ( Condition )

{

statement 1;

statement 2;

...

}

Flow Chart of if Statement:

Example of if Statement:

#include<stdio.h>

int main()

{

int a = 15, b = 20;

if ( b>a ) {

printf("b is greater");

}

return 0;

}

Output:

b is greater

if-else Statement:

If else statements in C is also used to control the program flow based on some condition, only the difference is: it's used to execute some statement code block if the expression is evaluated to true, otherwise executes else statement code block.

Syntax of if-else Statement:

if( condition )

{

Statement;

}

else

{

Statement;

}

Flow Chart of if-else Statement:

Example of if-else Statement:

#include<stdio.h> int main() { int a, b; printf("Please enter the value for a: \n"); scanf("%d", &a); printf("Please the value for b: \n"); scanf("%d", &b); if (a > b) { printf("a is greater \n "); }

else { printf("b is greater \n"); } }

Output of Program:-

Please enter the value for a : 5

Please enter the value for b : 10

b is greater

************Stay Tuned for upcoming Tutorial***********

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First Program in C

2021-09-24T06:42:00.003-07:00

Structure of Program

Sample Code of Print 'Hello World' in screen

#include<stdio.h>

int main()

{

printf("Hello World");

return 0;

}

Detail Description about program:

#include<stdio.h>	stdio is standard for input/output, this allows us to use some commands which includes a file called stdio.h. or This is a preprocessor command. That notifies the compiler to include the header file stdio.h in the program before compiling the source-code.
int/void main()	int/void is a return value, which will be explained in a while.
main()	The main() is the main function where program execution begins. Every C program must contain only one main function. or This is the main function, which is the default entry point for every C program and the void in front of it indicates that it does not return a value.
Braces	Two curly brackets "{...}" are used to group all statements. or Curly braces which shows how much the main() function has its scope.
printf()	It is a function in C, which prints text on the screen. or This is another pre-defined function of C which is used to be displayed text string in the screen.
return 0	At the end of the main function returns value 0.

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Operators in C

2021-09-24T06:30:00.002-07:00

Operators in C

C operators are symbols that are used to perform mathematical or logical manipulations. The C programming language is rich with built-in operators. Operators take part in a program for manipulating data and variables and form a part of the mathematical or logical expressions.

Types of Operators in C

C programming language offers various types of operators having different functioning capabilities.

Arithmetic Operators
Relational Operators
Logical Operators
Assignment Operators
Increment and Decrement Operators
Conditional Operator
Bitwise Operators
Special Operators

Arithmetic Operators

Arithmetic Operators are used to performing mathematical calculations like addition (+), subtraction (-), multiplication (*), division (/) and modulus (%).

Operator	Description
+	Addition
-	Subtraction
*	Multiplication
/	Division
%	Modulus

C Program to Add Two Numbers

Example:

#include <stdio.h>
void main()
{
 int i=3,j=7,k; /* Variables Defining and Assign values */
 k=i+j;
 printf("sum of two numbers is %d\n", k); 
}

Program Output:

Increment and Decrement Operators

Increment and Decrement Operators are useful operators generally used to minimize the calculation, i.e. ++x and x++ means x=x+1 or -x and x−−means x=x-1. But there is a slight difference between ++ or −− written before or after the operand. Applying the pre-increment first add one to the operand and then the result is assigned to the variable on the left whereas post-increment first assigns the value to the variable on the left and then increment the operand.

Operator	Description
++	Increment
−−	Decrement

Example: To Demonstrate prefix and postfix modes.

#include <stdio.h>
//stdio.h is a header file used for input.output purpose.

void main()
{
    //set a and b both equal to 5.
    int a=5, b=5;
    
    //Print them and decrementing each time.
    //Use postfix mode for a and prefix mode for b.
    printf("\n%d %d",a--,--b);
    printf("\n%d %d",a--,--b);
    printf("\n%d %d",a--,--b);
    printf("\n%d %d",a--,--b);
    printf("\n%d %d",a--,--b);
}

Program Output:

Relational Operators

Relational operators are used to comparing two quantities or values.

Operator	Description
==	Is equal to
!=	Is not equal to
>	Greater than
<	Less than
>=	Greater than or equal to
<=	Less than or equal to

Logical Operators

C provides three logical operators when we test more than one condition to make decisions. These are: && (meaning logical AND), || (meaning logical OR) and ! (meaning logical NOT).

Operator	Description
&&	And operator. It performs logical conjunction of two expressions. (if both expressions evaluate to True, result is True. If either expression evaluates to False, the result is False)
\|\|	Or operator. It performs a logical disjunction on two expressions. (if either or both expressions evaluate to True, the result is True)
!	Not operator. It performs logical negation on an expression.

Bitwise Operators

C provides a special operator for bit operation between two variables.

Operator	Description
<<	Binary Left Shift Operator
>>	Binary Right Shift Operator
~	Binary Ones Complement Operator
&	Binary AND Operator
^	Binary XOR Operator
\|	Binary OR Operator

Assignment Operators

Assignment operators applied to assign the result of an expression to a variable. C has a collection of shorthand assignment operators.

Operator	Description
=	Assign
+=	Increments then assign
-=	Decrements then assign
*=	Multiplies then assign
/=	Divides then assign
%=	Modulus then assign
<<=	Left shift and assign
>>=	Right shift and assign
&=	Bitwise AND assign
^=	Bitwise exclusive OR and assign
\|=	Bitwise inclusive OR and assign

Conditional Operator

C offers a ternary operator which is the conditional operator (?: in combination) to construct conditional expressions.

Operator	Description
? :	Conditional Expression

Special Operators

C supports some special operators

Operator	Description
sizeof()	Returns the size of a memory location.
&	Returns the address of a memory location.
*	Pointer to a variable.

Program to demonstrate the use of sizeof operator

Example:

#include <stdio.h>
void main()
{
      int i=10; /* Variables Defining and Assign values */      printf("integer: %d\n", sizeof(i));
}

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Variables in C

2021-09-24T06:23:00.004-07:00

Variables in C

A variable is nothing but a name given to a storage area that our programs can manipulate. Each variable in C has a specific type, which determines the size and layout of the variable's memory; the range of values that can be stored within that memory; and the set of operations that can be applied to the variable.

The name of a variable can be composed of letters, digits, and the underscore character. It must begin with either a letter or an underscore. Upper and lowercase letters are distinct because C is case-sensitive.

There are some rules to choosing a variable name

A variable name can consist of Capital letters A-Z, lowercase letters a-z, digits 0-9, and the underscore character.
The first character must be a letter or underscore.
Blank spaces cannot be used in variable names.
Special characters like #, $ are not allowed.
C keywords cannot be used as variable names.
Variable names are case sensitive.
Values of the variables can be numeric or alphabetic.
Variable type can be char, int, float, double, or void.

Based on the basic types explained in the previous chapter, there will be the following basic variable types −

Sr.No.	Type & Description
1	char Typically a single octet(one byte). It is an integer type.
2	int The most natural size of integer for the machine.
3	float A single-precision floating point value.
4	double A double-precision floating point value.
5	void Represents the absence of type.

Some examples are −

extern int d = 3, f = 5;    // declaration of d and f. 
int d = 3, f = 5;           // definition and initializing d and f. 
byte z = 22;                // definition and initializes z. 
char x = 'x';               // the variable x has the value 'x'.

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C - Data Types

2021-09-23T22:58:00.003-07:00

C - Data Types

Data types in c refer to an extensive system used for declaring variables or functions of different types. The type of a variable determines how much space it occupies in storage and how the bit pattern stored is interpreted.

The types in C can be classified as follows −

Sr.No.	Types & Description
1	Basic Types They are arithmetic types and are further classified into: (a) integer types and (b) floating-point types.
2	Enumerated types They are again arithmetic types and they are used to define variables that can only assign certain discrete integer values throughout the program.
3	The type void The type specifier void indicates that no value is available.
4	Derived types They include (a) Pointer types, (b) Array types, (c) Structure types, (d) Union types and (e) Function types.

The array types and structure types are referred collectively as the aggregate types. The type of a function specifies the type of the function's return value. We will see the basic types in the following section, where as other types will be covered in the upcoming chapters.

Integer Types

The following table provides the details of standard integer types with their storage sizes and value ranges −

Type	Storage size	Value range
char	1 byte	-128 to 127 or 0 to 255
unsigned char	1 byte	0 to 255
signed char	1 byte	-128 to 127
int	2 or 4 bytes	-32,768 to 32,767 or -2,147,483,648 to 2,147,483,647
unsigned int	2 or 4 bytes	0 to 65,535 or 0 to 4,294,967,295
short	2 bytes	-32,768 to 32,767
unsigned short	2 bytes	0 to 65,535
long	8 bytes or (4bytes for 32 bit OS)	-9223372036854775808 to 9223372036854775807
unsigned long	8 bytes	0 to 18446744073709551615

Floating-Point Types

The following table provide the details of standard floating-point types with storage sizes and value ranges and their precision −

Type	Storage size	Value range	Precision
float	4 byte	1.2E-38 to 3.4E+38	6 decimal places
double	8 byte	2.3E-308 to 1.7E+308	15 decimal places
long double	10 byte	3.4E-4932 to 1.1E+4932	19 decimal places

The header file float.h defines macros that allow you to use these values and other details about the binary representation of real numbers in your programs

The void Type

The void type specifies that no value is available. It is used in three kinds of situations −

Sr.No.	Types & Description
1	Function returns as void There are various functions in C which do not return any value or you can say they return void. A function with no return value has the return type as void. For example, void exit (int status);
2	Function arguments as void There are various functions in C which do not accept any parameter. A function with no parameter can accept a void. For example, int rand(void);
3	Pointers to void A pointer of type void * represents the address of an object, but not its type. For example, a memory allocation function void *malloc( size_t size ); returns a pointer to void which can be casted to any data type.

Sr.No.

Types & Description

Function returns as void

There are various functions in C which do not return any value or you can say they return void. A function with no return value has the return type as void. For example, void exit (int status);

Function arguments as void

There are various functions in C which do not accept any parameter. A function with no parameter can accept a void. For example, int rand(void);

Pointers to void

A pointer of type void * represents the address of an object, but not its type. For example, a memory allocation function void *malloc( size_t size ); returns a pointer to void which can be casted to any data type.

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Basic Syntax

2021-09-22T21:20:00.009-07:00

C - Basic Syntax

You have seen the basic structure of a C program, so it will be easy to understand other basic building blocks of the C programming language.

Tokens in C

A C program consists of various tokens and a token is either a keyword, an identifier, a constant, a string literal, or a symbol. For example, the following C statement consists of five tokens −

printf("Hello, World! \n");

The individual tokens are −

printf

(

"Hello, World! \n"

)

;

Semicolons

In a C program, the semicolon is a statement terminator. That is, each individual statement must be ended with a semicolon. It indicates the end of one logical entity.

Given below are two different statements −

printf("Hello, World! \n");

return 0;

Comments

Comments are like helping text in your C program and they are ignored by the compiler. They start with /* and terminate with the characters */ as shown below −

/* my first program in C */

You cannot have comments within comments and they do not occur within a string or character literals.

Identifiers

A C identifier is a name used to identify a variable, function, or any other user-defined item. An identifier starts with a letter A to Z, a to z, or an underscore '_' followed by zero or more letters, underscores, and digits (0 to 9).

C does not allow punctuation characters such as @, $, and % within identifiers. C is a case-sensitive programming language. Thus, Manpower and manpower are two different identifiers in C. Here are some examples of acceptable identifiers −

mohd       zara    abc   move_name  a_123
myname50   _temp   j     a23b9      retVal

Keywords

The following list shows the reserved words in C. These reserved words may not be used as constants or variables or any other identifier names.

auto	else	long	switch
break	enum	register	typedef
case	extern	return	union
char	float	short	unsigned
const	for	signed	void
continue	goto	sizeof	volatile
default	if	static	while
do	int	struct	_Packed
double

Whitespace in C

A line containing only whitespace, possibly with a comment, is known as a blank line, and a C compiler totally ignores it.

Whitespace is the term used in C to describe blanks, tabs, newline characters and comments. Whitespace separates one part of a statement from another and enables the compiler to identify where one element in a statement, such as int, ends and the next element begins. Therefore, in the following statement −

int age;

there must be at least one whitespace character (usually a space) between int and age for the compiler to be able to distinguish them. On the other hand, in the following statement −

fruit = apples + oranges; // get the total fruit

no whitespace characters are necessary between fruit and =, or between = and apples, although you are free to include some if you wish to increase readability.

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Structure of C Program

2021-09-22T01:25:00.016-07:00

Structure of C Program

A C program basically consists of the following parts −

Preprocessor Commands
Functions
Variables
Statements & Expressions
Comments

Let us look at a simple code that would print the words "Hello World" −

#include <stdio.h>

int main() {

/* my first program in C */

printf("Hello, World! \n");

return 0;

}

Let us take a look at the various parts of the above program −

The first line of the program #include <stdio.h> is a preprocessor command, which tells a C compiler to include stdio.h file before going to actual compilation.
The next line int main() is the main function where the program execution begins.
The next line /*...*/ will be ignored by the compiler and it has been put to add additional comments in the program. So such lines are called comments in the program.
The next line printf(...) is another function available in C which causes the message "Hello, World!" to be displayed on the screen.
The next line return 0; terminates the main() function and returns the value 0.

Compile and Execute C Program

Let us see how to save the source code in a file, and how to compile and run it. Following are the simple steps −

Open a text editor and add the above-mentioned code.
Save the file as hello.c
Open a command prompt and go to the directory where you have saved the file.
Type gcc hello.c and press enter to compile your code.
If there are no errors in your code, the command prompt will take you to the next line and would generate a.out executable file.
Now, type a.out to execute your program.
You will see the output "Hello World" printed on the screen.

$ gcc hello.c
$ ./a.out
Hello, World!

Make sure the gcc compiler is in your path and that you are running it in the directory containing the source file hello.c.

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C - Environment Setup

2021-09-22T00:55:00.008-07:00

C - Environment Setup

Local Environment Setup

If you want to set up your environment for C programming language, you need the following two software tools available on your computer, (a) Text Editor and (b) The C Compiler.

Text Editor

This will be used to type your program. Examples of few a editors include Windows Notepad, OS Edit command, Brief, Epsilon, EMACS, and vim or vi.

The name and version of text editors can vary on different operating systems. For example, Notepad will be used on Windows, and vim or vi can be used on windows as well as on Linux or UNIX.

The files you create with your editor are called the source files and they contain the program source codes. The source files for C programs are typically named with the extension ".c".

Before starting your programming, make sure you have one text editor in place and you have enough experience to write a computer program, save it in a file, compile it and finally execute it.

The C Compiler

The source code written in source file is the human readable source for your program. It needs to be "compiled", into machine language so that your CPU can actually execute the program as per the instructions given.

The compiler compiles the source codes into final executable programs. The most frequently used and free available compiler is the GNU C/C++ compiler, otherwise you can have compilers either from HP or Solaris if you have the respective operating systems.

The following section explains how to install GNU C/C++ compiler on various OS. We keep mentioning C/C++ together because GNU gcc compiler works for both C and C++ programming languages.

Installation on Windows

To install GCC on Windows, you need to install MinGW. To install MinGW, go to the MinGW homepage, www.mingw.org, and follow the link to the MinGW download page. Download the latest version of the MinGW installation program, which should be named MinGW-<version>.exe.

While installing Min GW, at a minimum, you must install gcc-core, gcc-g++, binutils, and the MinGW runtime, but you may wish to install more.

Add the bin subdirectory of your MinGW installation to your PATH environment variable, so that you can specify these tools on the command line by their simple names.

After the installation is complete, you will be able to run gcc, g++, ar, ranlib, dlltool, and several other GNU tools from the Windows command line.

*********Stay Tuned for Upcoming Tutorials***********

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C Programming Tutorial Zero to Hero

2021-09-21T23:32:00.018-07:00

C Programming Tutorial Zero to Hero

What is C:

C is one of the fastest programming language as it is close to low-level languages such as Assembly language. If you are already familiar with programming, then you must know the demand out there for a C programmer. Because C comes in handy in case of all the applications that require fast processing, such as games, or major parts of different operating systems.

Benefits of C:

C was developed in early 1970’s Brian Kernighan and Dennis Ritchie produced the first publicly available description of C, now known as the K&R standard.

C takes only significant CPU time for interpretation. That is why a lot Python libraries such as NumPy, pandas, scikit-learn, etc. are built using C.
Being close to Machine language, some of its functions including direct access to machine level hardware APIs
It is a highly portable language
Data structure and algorithm can be better implemented in C language.
C is being used to support other programming languages to enhance their efficiency.

Scope:

Windows, Linux, Mac all are mostly written in C. Linux is written 97% using C.
C has also been used widely while creating iOS and Android kernels.
MySQL database is written using C.
Ruby and Pearl are mostly written using C.
Most part of Apache and NGINX is written using C.
Embedded Systems are created using C

Control:

C gives most of the control in the hand of users. Things like memory allocation and manipulation are totally in the hands of the programmer. Being a flexible language, it provides more access to the programmer because of which it is more efficient.

All of these reasons make C one of the widely used Programming language having special respect in the heart of programmers.

C Programs

A C program can vary from 3 lines to millions of lines and it should be written into one or more text files with extension ".c"; for example, hello.c. You can use "vi", "vim" or any other text editor to write your C program into a file.
This tutorial assumes that you know how to edit a text file and how to write source code inside a program file.

*Stay Tuned for Upcoming Tutorials***

Commonly asked C Programming Interview Questions

2020-12-30T03:28:00.003-08:00

Commonly asked C #Programming Interview Questions

1] WHAT IS C LANGUAGE?

C is a mid-level and procedural programming language. The procedural programming language is also known as the structure programming language is a technique in which large programs are broken down into smaller modules. and each module uses structured code.

2] WHAT IS NULL POINTER?

Null is used to indicate that the pointer doesn't point to avoid location. Ideally, we should initialize pointers as Null if we don't known their value at the time of declaration.

3] WHAT IS MEMORY LEAK? WHY IT SHOULD BE AVOIDED

Memory leak occurs when programmers create a memory in heap and forget to delete it. Memory leak are particularly serious issues for programs like daemons and servers which by definition never terminate.

4] CAN PROGRAM BE COMPILED WITHOUT MANI() FUNCTION?

Yes. it can be but cannot be executed, as the execution require main() function definition.

Next Part Coming Soon... stay tune

Pattern

2020-08-27T00:57:00.003-07:00

Code:

#include <stdio.h>
int main()
{
int n, x, y;
printf("Enter any number: ");
scanf("%d", &n);

if (n % 2 == 0)
n = n + 1;

for (y = 3 * n / 2; y >= -3 * (n / 2); y--)
{
for (x = -3 * (n / 2); x <= 3 * (n / 2); x++)
{
if ((x >= -1 * n / 2 && x <= n / 2) || (y >= -1 * n / 2 && y <= n / 2))
{
if (x == y || x == -y)
printf("@ ");
else if ((y <= 0 || y >= n / 2) && (x + y == n - 1))
printf("@ ");
else if ((y >= 0 || y <= -n / 2) && (x + y == 1 - n))
printf("@ ");
else if ((x <= 0 || x >= n / 2) && (x - y == n - 1))
printf("@ ");
else if ((x >= 0 || x <= -n / 2) && (x - y == 1 - n))
printf("@ ");
else
printf(" ");
}
else
{
if (x + y == (n - 1) * 2)
printf("@ ");
else if (x + y == (1 - n) * 2)
printf("@ ");
else if (x - y == (n - 1) * 2)
printf("@ ");
else if (x - y == (1 - n) * 2)
printf("@ ");
else
printf(" ");
}
}
printf("\n");
}
}

Left and Right Arrows

2020-06-15T20:37:00.005-07:00

#4 Left and Right Arrows

Input :7 (Must be odd)

Output:

Program solution for Left Right Arrow

#include <stdio.h>

int main()

{

int i, j, n;

printf("Enter Number: ");

scanf("%d", &n); // ‘n’ must be odd

int num1 = n / 2 * 3;

// right arrow

printf("Right Arrow\n");

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

{

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

{

// center horizontal, upper right diagonal, bottom right diagonal

if(i == n / 2 || j - i == n / 2 || i + j == num1)

printf("*");

else

printf(" ");

}

printf("\n");

}

// left arrow

printf("Left Arrow\n");

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

{

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

{

// center horizontal, bottom left diagonal, upper left diagonal

if(i == n / 2 || i - j == n / 2 || i + j == n / 2)

printf("*");

else

printf(" ");

}

printf("\n");

}

return 0;

}

Diagonal & Sides of a Rhombus/Diamond

2020-06-10T05:17:00.003-07:00

#3 Diagonal & Sides of a Rhombus/Diamond

Input: 9 (input should be an odd number only, else the desired output will not be obtained)

Output:

Diagonal & Sides of a Rhombus/Diamond :

#include <stdio.h>

int main()

{

int i, j, n;

printf("Enter Number : ");

scanf("%d", &n); // ‘n’ must be odd

int num1 = n / 2 * 3;

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

{

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

{

// center horizontal, center vertical, upper left diagonal, bottom left diagonal, upper right diagonal, bottom right diagonal

if(i == n / 2 || j == n / 2 || i + j == n / 2 || i - j == n / 2 || j - i == n / 2 || i + j == num1)

printf("*");

else

printf(" ");

}

printf("\n");

}

return 0;

}

Diagonal & Sides of a Rectangle

2020-06-10T02:26:00.005-07:00

#2 Diagonal & Sides of a Rectangle

Input: 7 (input should be an odd number only, else the desired output will not be obtained)

output:

Program For Diagonal & Slides of a Rectangle:

#include <stdio.h>

int main()

{

int i, j, n;

printf("Enter number:");

scanf("%d", &n); // 'n' must be odd

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

{

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

{

// left diagonal, right diagonal, top horizontal, bottom horizontal, left vertical, right vertical

if(i == j || i + j == n - 1 || i == 0 || i == n - 1 || j == 0 || j == n - 1)

printf("*");

else

printf(" ");

}

printf("\n");

}

return 0;

}

Butterfly Pattern Printing

2020-06-09T23:37:00.003-07:00

#1 Butterfly Pattern Printing

Input : 5

Output:

Program For Butterfly Pattern Printing:

#include <stdio.h>
int main()
{
int i, j, n;
printf("Enter Number: ");
scanf("%d", &n);
// upper half of the pattern
for(i = 0; i < n; i++)
{
for(j = 0; j < (2 * n); j++)
{
if(i >= j) // upper left triangle
printf("*");
else
printf(" ");
if(i >= (2 * n - 1) - j) // upper right triangle
printf("*");
else
printf(" ");
}
printf("\n");
}
// bottom half of the pattern
for(i = 0; i < n; i++)
{
for(j = 0; j < (2 * n); j++)
{
if(i + j <= n - 1) // bottom left triangle
printf("*");
else
printf(" ");
if((i + n) <= j) // bottom right triangle
printf("*");
else
printf(" ");
}
printf("\n");
}
return 0;
}