Converts a character to uppercase.

    Format

      #include  <ctype.h>

      int toupper  (int character);

1 - Argument

 character

    An object of type int representable as an unsigned char or the
    value of EOF. For any other value, the behavior is undefined.

2 - Description

    If the argument represents a lowercase letter, and there is
    a corresponding uppercase letter, as defined by character
    type information in the program locale category LC_CTYPE, the
    corresponding uppercase letter is returned.

    If the argument is not a lowercase character, it is returned
    unchanged.

3 - Return Value

    x                  The uppercase letter corresponding to the
                       argument. Or, the unchanged argument, if the
                       argument is not a lowercase character.