
Returns the starting position of the first occurrence of
string_exp1 within string_exp2. The search for the first occurrence
of string_exp1 begins with the first character position in string_exp2
unless the optional argument, start, is specified.
If start is specified, the search begins with the character
position indicated by the value of start.
The first character position in string_exp2 is indicated by the value 1.
If string_exp1 is not found within string_exp2, the value 0 is returned.
	