INDEX

 INDEX (string, substring [,back] [,kind])

 Class:  Elemental function - Generic

 Returns the starting position of the substring as an INTEGER*4 or
 INTEGER*8 value.

 "string" and "substring" are of type character, "back" is of type
 logical, and "kind" is a scalar integer initialization expression.

 The result is of type integer.  If "kind" is present, the kind
 parameter of the result is that specified by "kind"; otherwise, the
 kind parameter of the result is that of default integer.  If the
 processor cannot represent the result value in the kind of the
 result, the result is undefined.

 If "back" is absent or false, the leftmost substring is found. If
 "back" is true, the rightmost substring is found. 

 Examples:

 INDEX ('FORTRAN', 'O', BACK = .TRUE.) has the value 2.

 INDEX ('XXXX', " ", BACK = .TRUE.) has the value 0.

 INDEX ('XXXX', "", BACK = .TRUE.) has the value 5.