tag:blogger.com,1999:blog-47801343345937793562024-08-28T04:00:31.034-07:00History Of Computerhistory-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.comBlogger220125tag:blogger.com,1999:blog-4780134334593779356.post-90019579122502563342013-10-17T20:07:00.001-07:002013-10-17T20:07:15.414-07:00MID$ function
The MID$ function returns a string of m characters from x$ string, beginning with the n th character.
Syntax
LN MID$ (x$,n,m)
Where,
LN : Line Number
x$ : string from which the m characters are to be extracted starting from nth character.
n : the position from which character are to be extracted.
m : number of character.
n must be within the range 1 to 255.
m history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-8166988574938215052013-10-12T19:04:00.000-07:002013-10-12T19:04:43.718-07:00Right$ function
The RIGHT$ function returns the rightmost n characters of string x$.
Syntax
LN RIGHT (x$, n)
Where ,
LN : Line Number
x$ : string from which the n right most characters are to be extracted.
n : number of characters
The value of n must be within the range of 0 to 255
if n = 0, the null string (length zero) is returned.history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-1753207323270477152013-09-30T19:25:00.003-07:002013-09-30T19:25:38.269-07:00String Functions(String handling commands
String functions or string handling commands allows us to examine and modify tring and convert tring to numeric values.
The string function with a dollar sign($) at the end returns a string whereas a string function without a dollar sign returns a numeric value.
String operation allow combination and comparison of strings.BASIC has the following string manipulation function.
LEFT$ function
history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com1tag:blogger.com,1999:blog-4780134334593779356.post-20400619393260660832013-08-28T19:38:00.000-07:002013-08-28T19:38:08.020-07:00Functions and Subroutines
A function is an operation which produces a single result on some data and can be used as part of an expression. BASIC provides a large number of utility functions which are part of BASIC language and are known as Built-in function (or Library functions). The data upon which the function acts to produce the desired result is known as argument of the function. The argument can be a history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-79660518659136336802013-08-09T02:23:00.003-07:002013-08-09T02:23:51.364-07:00WHILE-WEND statement
The WHILE-WEND statement executes a series of statements in a loop as long as given condition is true.
Syntax
LN WHILE expression
.
.
.
[loop statements]
.
.
.
WEND
Where ,
LN : Line Number
expression : valid BASIC expression
loop statement : Series of statement which are to be repeated
Points to Remember
If expression is true, loop history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-74380304176890385232013-08-05T19:36:00.000-07:002013-08-08T04:23:13.303-07:00IF...THEN..ELSE statement
The IF..THEN..ELSE statement allows us to make the decision regarding program flow based on the result returned by an expression.
Syntax
LN IF expression (,) THEN statement(,) ELSE statement
if the result of expression is true, the THEN statement is executed.
if the result of expression is false, the THEN line number is ignored and the ELSE line number is executed.
THEN and ELSE may be history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-8791718784286135392013-08-01T02:06:00.000-07:002013-08-02T02:00:26.553-07:00IF...THEN statement
The IF... THEN statement allows us to make a decision regarding program flow based on the result returned by an expression.
Syntax
LN IF expression [,] THEN statement[,]
Points to remember
If the result of expression is true (or non zero), THEN then statement is executed.
If the result of the expression is false (or zero), the THEN statement is ignored and execution continues with the nexthistory-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-37826072552507765312013-07-27T02:45:00.000-07:002013-07-27T23:50:56.793-07:00FOR and NEXT statements
The FOR and NEXT statement is used to execute a series of instructions a specified number of times in a loop.
Syntax
LN FOR variable = X To Y [STEP Z]
.
.
.
NEXT [variable][,variable...]
Where,
LN : Line Number
variable : variable used as a counter
X, Y and Z :numeric expressions
STEP Z : specifies the counter increment for eachhistory-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-50885121002892102742013-07-18T03:08:00.001-07:002013-07-18T03:08:59.811-07:00ON...GOTO Statement
The ON...GOTO Statement is used to branch to one of several specified line numbers depending on the value return, when an expression is evaluated.
Syntax
LN ON expression GOTO line numbers
Where,
LN : Line Number
Expression : Valid numeric expression
Line number : Line numbers to where jump has to take place.
In the ON...GOTO statement the history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-16315572776516651332013-07-13T05:18:00.001-07:002013-07-13T05:18:59.723-07:00Branching and Looping
Introduction
In a computer program the statement are ordinarily executed line by line. In BASIC language the execution is done in the ascending order of line number, unless instructed otherwise by control statement. The control sequence of statement executed can be altered by means of control statement.
A transfer of control or jump from one part of the program to another is referred as history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-91798834501397748212013-07-07T21:33:00.001-07:002013-07-07T21:33:34.984-07:00SWAP Statement
The SWAP statement is used to exchange the values of two variables.
Syntax
LN SWAP variable1, varaible2
Where,
LN : Line Number
variable1 : the first variable
variable2 : the second variable
Any type of variable may be swapped (numeric or string).
To use SWAP, the two variables must be of the same type.
Use of SWAP statement in history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-14871351753595867932013-07-06T04:08:00.000-07:002013-07-06T04:08:05.596-07:00RESTORE Statement
The restore statement allows DATA statements to be reread from a specified line.
Syntax
LN RESTORE [Line Number]
Where,
LN : Line Number
Line number : The particular line number from which data are to be read again.
if line number is specified the next READ statement reads the first data in the history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-36654706115383172972013-06-30T02:55:00.001-07:002013-06-30T02:55:34.753-07:00READ and DATA statement
The READ statement is used to read value from a DATA statement and assign them to variables.
The DATA statement is used to store the numeric, integer or string constants that are accessed by the READ statement.
Syntax
LN READ list of variable
LN DATA constants
Where,
LN : Line Number
list of variables : numeric or string variables
Constants : numeric or history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-23157527967079272072013-06-19T04:10:00.000-07:002013-06-19T04:10:47.085-07:00INPUT Statement
The INPUT Statement is used to prepare the program for input from the keyboard during program execution.
Syntax
LN INPUT [Prompt string ;] List of Variables
Where,
LN : Line Number
Prompt String : Message displayed for data to be supplied during program execution.
List of Variable : Contains the variable {s} that store data
The history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-61974272203888070892013-06-05T02:00:00.002-07:002013-06-05T02:00:21.721-07:00LET statement
The LET statement assigns the value of an expression to a variable.
Syntax
LN [LET] Variable = expression
Where,
LN : Line Number
[LET] : LET is optional (i.e. the equal sign(=) is sufficient to assign an expression to a variable.
Variable : Stores the values of expression on the right hand side.
Expression valid BASIC history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-14843007333761142192013-06-02T07:22:00.000-07:002013-06-02T07:22:28.612-07:00TAB Function
The TAB function spaces to position on the screen.
Syntax
LN TAB (n)
Where,
LN : Line Number
n : number of spaces
Space 1 is the left most position.
n must be within the range of 1 to 255.
if the current print position is already beyond space n, TAB goes to that position on the next line.
TAB should be used with PRINT statement.
history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-10775203264069383992013-05-29T22:49:00.000-07:002013-05-29T22:49:02.814-07:00Reading and Printing
Introduction
In a computer program it is often necessary to supply data to the program and print the result. This is done by input and output statements. In a BASIC program data can be supplied by INPUT, READ,DATA, RESTORE statements and printed with PRINT and LNPRINT statement.
PRINT Statement
The PRINT statement is used to output a display on the screen.
Syntax
LN PRINT [list of expression] [history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-21372894728110668682013-05-19T17:50:00.000-07:002013-05-19T17:50:01.993-07:00End Statement
The END statement terminates program execution , closes all files and returns to the command level.
Syntax
END
Generally, the END statement indicates the end of a BASIC program.
END statement may be placed any where in the program to terminate execution.
END closes all files.
GW - BASIC always returns to the command level after END is executed.
Example 2
. &history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-10082458717335196012013-05-07T02:36:00.000-07:002013-05-07T02:36:56.404-07:00BASIC Statements
Program comments - the REM Statement
The REM statement allows remarks to be inserted in program.
Syntax
LN REM [comment]
' [comment]
Where,
LN : Line Number
Comment : Remarks written by the programmer
' : Apostrophe (') may be used in place of REM.
Points to&history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-6963329272256075412013-05-05T17:48:00.001-07:002013-05-05T17:48:20.414-07:00RM DIR Command
The RMDIR Command is used to delete a sub directory.
Syntax
RMDIR pathname
Where,
Path name : Location of sub directory to be removed (deleted)
The path name must not exceed 63 characters.
The sub directory is to be removed from its present directory
The sub directory to be deleted must be empty (i.e. with no files)
Example 27
1. RMDIR CLASS IX (press enter key)
It is used to deletehistory-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-15603547486854665152013-05-03T22:41:00.000-07:002013-05-03T22:41:04.692-07:00CH DIR command
The CHDIR command is used to change from one working directory to another
Syntax
CHDIR path name
Where,
path name : Location of sub directory to be changed into.
The path name can have maximum 63 characters.
Example 26
1. CHDIR "CLASS IX" (press enter key)
It is used to change to sub directory CLASS X from current directory.
2. CHDIR " C : \ GWBASIC" (press enter key)
It is used history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-48560378109301935582013-04-30T00:42:00.002-07:002013-04-30T00:42:35.705-07:00MKDIR Command
The MKDIR is used to create a sub directory.
Syntax
MKDIR Path name
Where,
Path name : Location of the sub directory to be created.
path name must not exceed 63 characters.
sub directory can be created in a default drive or in other drives.
Example 25
1. MKDIR "CLASSIX" (press enter key)
Creates sub directory GWBASIC inside the current directory.
2. MKDIR "C : GWBASIC CLASS X" (history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-56249462191473188982013-04-27T18:39:00.000-07:002013-04-27T18:39:02.178-07:00Additional Commands
LOAD Command
The LOAD command is used to load a file from A diskette or hard disk into the memory.
Syntax
LOAD file name (,r)
Where,
file name : The name of file to be loaded.
r : This option runs the program.
Points to remember
If the extension is omitted while writing the file name , the file having the same name with extension .BAS will be loaded.
LOAD command closes all openhistory-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-16369133166017886462013-04-22T04:11:00.000-07:002013-04-22T04:11:30.092-07:00CONT
The CONT command is used to continue program execution after a break.
Syntax
CONT
Resumes program execution after CTRL+C, STOP or END halts a program.
Execution continues at the point where the break occurs..
CONT is useful in debugging, it lets you to set break point with the STOP statement , OR use GOTO to resume execution at a particular line number.
history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0tag:blogger.com,1999:blog-4780134334593779356.post-15562728684494295122013-04-15T05:05:00.000-07:002013-04-15T05:05:22.188-07:00SOUND
The sound command is used to generate sound through the speaker.
Syntax
SOUND freq. duration
Where ,
freq. : The desired frequency in hertz (Cycles per second)
duration : The desired duration in clock ticks.
freq. is a numeric expression within the range of 37 to 32,767.
clock ticks occurs 18.2 times per second.
duration must be expressed within the range of 0 to 65,535.
Example history-ofcomputer.blogspot.comhttp://www.blogger.com/profile/02125600287306528114noreply@blogger.com0