Q(uick)BASIC Function: SQR

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SQR

A math function that returns the square root of numeric expression

Worth knowing

Useful and cross-version information about the programming environments of QBasic and QuickBasic.

Syntax

SQR(numeric-expression)

Description/Parameter(s)

numeric-expression

A value greater than or equal to zero.

Example

PRINT SQR(25), SQR(2) 'Output is: 5 1.414214

Syntax

SQR(numeric-expression)

Description/Parameter(s)

The argument n must be >= 0.

Example

The following program plots the graphs ofy = √-x for -9 <= x < 0, and
y = √x for 0 <= x <= 9:

'*********************************************************************
' Example program for SQR function.
'*********************************************************************
SCREEN 1 : COLOR 1           'Low-resolution color graphics mode.
WINDOW (-9,-.25)-(9,3.25)    'Convert screen to Cartesian coordinates.
LINE (-9,0)-(9,0)            'Draw X-axis.
LINE (0,-.25)-(0,3.25)       'Draw Y-axis.
FOR X = -9 TO 9
    LINE(X,.04)-(X,-.04)     'Put tick marks on X-axis.
NEXT
FOR Y = .25 TO 3.25 STEP .25
    LINE (-.08,Y)-(.12,Y)    'Put tick marks on Y-axis.
NEXT
PSET (-9,3)                  'Plot the first point of function.
FOR X = -9 TO 9 STEP .25
    Y = SQR(ABS(X))          'SQR argument cannot be negative.
    LINE -(X,Y),2            'Draw a line to the next point.
NEXT

Syntax

SQR(numeric-expression)

Description/Parameter(s)

numeric-expression

A value greater than or equal to zero.

Example

The following program uses the SQR function to plot the graph of
y = sqr(abs(x)) for -9 <= x <= 9.

SCREEN 1: COLOR 1            'Low-resolution color graphics mode.
WINDOW (-9, -.25)-(9, 3.25)  'Convert screen to Cartesian coordinates.
LINE (-9, 0)-(9, 0)          'Draw X-axis.
LINE (0, -.25)-(0, 3.25)     'Draw Y-axis.
FOR X = -9 TO 9
    LINE (X, .04)-(X, -.04)  'Put tick marks on X-axis.
NEXT X
FOR Y = .25 TO 3.25 STEP .25
    LINE (-.08, Y)-(.12, Y)  'Put tick marks on Y-axis.
NEXT Y
PSET (-9, 3)                 'Plot the first point of function.
FOR X = -9 TO 9 STEP .25
    Y = SQR(ABS(X))          'SQR argument cannot be negative.
    LINE -(X, Y), 2          'Draw a line to the next point.
NEXT X