BASIC-DOS

BASIC-DOS BASIC Commands

IF

The IF statement evaluates expression, and if the result is TRUE (non-zero), it executes the statement(s) following the THEN keyword; otherwise, it executes the statement(s) following the ELSE keyword, if any:

IF expression THEN statement(s) [ELSE statement(s)]

Multiple statements are separated by colons, and they all belong to the IF statement, up to the ELSE keyword (or the end of the line).

Relational operators (eg, =, <>, <, and >=) produce -1 for TRUE and 0 for FALSE, and logical operators (AND, OR, XOR, EQV, IMP, and NOT) operate on all the bits of their operands. See Operators.

Example:

IF A$ = "Y" THEN PRINT "Yes" ELSE PRINT "No":GOTO 100

As in Microsoft BASIC, a line number by itself after THEN (eg, IF X THEN 100) is the same as THEN GOTO 100.

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