NAME

instr - find one string in another

SYNOPSIS

v = instr([NumExpr,] StrExpr1, StrExpr2)

DESCRIPTION

Instr returns the index into the StrExpr1 where the string StrExpr2 first occurs.  If NumExpr is given, StrExpr1 is examined beginning at character position NumExpr.  Otherwise, StrExpr1 is examined beginning at character position 1. 

NumExpr may be any numeric expression.  StrExpr1 and StrExpr2 may be any string expressions.  If NumExpr > len(StrExpr1), or if StrExpr1 is null, or if StrExpr2 cannot be found, instr returns 0.  If StrExpr2 is null, instr returns NumExpr (or 1 if NumExpr is not specified). 

EXAMPLE

The program

	x$ = "Basmark Corporation"
	y$ = "rat"
	print instr(x$, y$); instr(16, x$, y$)

produces

	 14  0

since the first "rat" occurs at position 14 in string x$, and there is no "rat" at or after position 16. 

DIAGNOSTICS

If NumExpr is less than 1, an "Illegal function call" error occurs. 

from The Basmark QuickBASIC Programmer’s Manual by Lawrence Leinweber