02 · REMEMBER A VALUE

Variables and expressions

Give values names in BASIC, work with numeric expressions, and use string variables with a dollar-sign suffix.

Try these BASIC examples in the Web IDE Terminal.

Give a value a name

A variable lets a program remember a value. Assignment evaluates the expression on the right of = and stores it under the name on the left.

BASIC

x = 25
PRINT x * 4

The numeric result is 100. Classic BASIC numeric output may include spacing; the value is the point of this example.

In classic BASIC syntax, a dollar sign at the end of a variable name marks a string variable. Use + to join strings.

BASIC

name$ = "Cortex"
PRINT "Hello, " + name$ + "."

The expected text is Hello, Cortex.. A string is text, even when it contains digits.

Expressions combine values, variables, and operators. Parentheses make the intended grouping explicit.

BASIC

rectWidth = 12
rectHeight = 8
area = rectWidth * rectHeight
perimeter = 2 * (rectWidth + rectHeight)
PRINT area
PRINT perimeter

The numeric results are 96 and 40. Cortex uses QBASIC-style typing and coercion rules. Use HELP in Terminal for language reference entries.

Change width or height and predict both results before running the program. Then learn how to repeat work with a loop.