# Fortran Wiki verify

## Description

Verifies that all the characters in a string are present in a set.

If back is either absent or equals false, this function returns the position of the leftmost character of string that is not in set. If back equals true, the rightmost position is returned. If all characters of set are found in string, the result is zero.

## Standard

Fortran 95 and later, with kind argument Fortran 2003 and later

## Class

Elemental function

## Syntax

result = verify(string, set[, back [, kind]])

## Arguments

• string - Shall be of type character.
• set - Shall be of type character.
• back - (Optional) shall be of type logical.
• kind - (Optional) An integer initialization expression indicating the kind parameter of the result.

## Return value

The return value is of type integer and of kind kind. If kind is absent, the return value is of default integer kind.

## Example

program test_verify
write(*,*) verify("fortran", "ao")           ! 1, found 'f'
write(*,*) verify("fortran", "foo")          ! 3, found 'r'
write(*,*) verify("fortran", "c++")          ! 1, found 'f'
write(*,*) verify("fortran", "c++", .true.)  ! 7, found 'n'
write(*,*) verify("fortran", "fortran")      ! 0' found none
end program