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QBASIC WINDOW

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QBASIC

KEY WORDS IN QBASIC LET

(CLICK HERE TO VIEW EXAMPLE PROGRAM)

REM

CLS

INPUT

PRINT END

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DEFINITION OF SOME KEYWORDS

REM : Remark statement . Givescomment for the program

CLS : Clear screen.INPUT: Gets input from the user.

PRINT: Used to print on the standard

monitor.

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VARIABLES

Its value changes during theexecution of the program.

Variables are of two types

They are String variable and Numeric

variable.

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Variables

Numeric variable String variable

E.g. a=5 E.g. a$=HELLO

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CONSTANTS

Integer constant

Numeric constant

String constant

In BASIC there are threetypes of constants.

They are

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Rules of Basic constants

The maximum number of digits in a numericconstant is 8.

Commas and blanks are not allowed in numericconstant.

Usage of + sign is optional ,but sign should beused if the number is negative.

Basic does not have any difference betweeninteger and fractional numbers

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QBASIC

CONSTANTS Examples

NUMERIC: 936 -18 17.284.538E-11

String: "John Smith" "Smith,John" "23 Oak Dr."

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QBASIC STATEMENTSLET

LET variable = expression algebraic or string

X = A + B * C

PRINT

PRINT output list for any type of output

PRINT Hello; N$

LPRINT same as above For output to the printer seesamples in handout

END : END last

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REM : REM or ' followed bycomments documentation or

explanation

e.g. REM Program to compute area

INPUT : INPUT variable-list simpleinput from keyboard

INPUT A, B$

INPUT Name :, N$

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CLS : CLS clears the screen

SCREENSCREEN sets up graphics SCREEN 12

SCREENSCREEN n sets up graphics SCREEN 12

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PSET

PSE

T (x-coord, y-coord), color point (pixel)PSET (200, 100), 3

LINE

LINE

(x1,y1)-(x2,y2), color line LINE (10, 20) - (50, R), 4

LINE (x1,y1)-(x2,y2), color, B outlined box

LINE

(10, 20) - (50, R), 4, B LINE (x1,y1)-(x2,y2), color, BF filled in box

LINE (20,10) - (10,5), 4,

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CIRCLE

CIRCLE (xcenter,ycenter), radius, colorcircle

CIRCLE (100, 50), 20, 3Screen 0

Text Mode

1 320 by 200 4 color

2 640 by 200 B/W

9 640 by 350 16 color 12 640 by 480 16 color

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Colors: 0 Black 8 Gray

1 Blue 9 Light Blue

2 Green 10 Light green 3 Cyan 11 Light cyan

4 Red 12 Light red

5 Magenta 13 Light magenta

6 Brown 14 Yellow

7 White 15 Bright white

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Sound BEEP

SOUND 4000, 100

frequency, durationchaining to differentmodules

(Click here to view a sample program)

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FUNCTIONS

Mathematical

Operations +-*/^

Y = SQR(X) is the same as[] yx=INTY = INT(X) is the same as,the integerpart of a number

RND This produces a random numberfrom 0 to 1.yx=SQR

Y = SQR(X) is the same

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String

LEFT$

A$ = LEFT$(Calculus,3) gives Cal

LENN = LEN(Calculus) gives 8

MID$

A$ = MID$(Calculus,4,2) gives cu

RIGHT$ A$ = RIGHT$(Calculus,2) gives us

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Sound and Music

BEEP PLAY SOUND

Printer

LPRINT LPRINT USING

Functions (Numeric)

ABS ASC ATN CDBL CINTCOS EXP FIXINT LOGRND SGN SIN SQR TAN

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Functions (String) CHR$ LCASE$ LEFT$ LEN MID$

RIGHT$ SPACE$ STRING$

UCASE$ Formatting

SPC TAB

Operators

AND MOD NOT OR

QBASIC

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COMMON STATEMENTS

Graphics and Screen

Display CIRCLE

CLS COLOR LINE LOCATE

PRINT PRINT USING PSET

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Files

CLOSE GET INPUT# LINE INPUT#

OPEN PRINT# WRITE#

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CLICK HERE TO SEE A COMPUTER MAN PROGRAM

TALKING TO YOU!!