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Synopsis:
    #include <ctype.h>
    int isdigit( int c );

Description:
    The isdigit function tests for any decimal-digit character '0' through
    '9'.

Returns:
    The isdigit function returns a non-zero value when the argument is a
    digit; otherwise, zero is returned.

See Also:
    isalnum, isalpha, iscntrl, isgraph, islower, isprint, ispunct, isspace,
    isupper, isxdigit, tolower, toupper

Example:
    #include <stdio.h>
    #include <ctype.h>

    char chars[] = {
        'A',
        '5',
        '$'
    };

    #define SIZE sizeof( chars ) / sizeof( char )

    void main()
      {
        int   i;

        for( i = 0; i < SIZE; i++ ) {
          printf( "Char %c is %sa digit character\n",
                chars[i],
                ( isdigit( chars[i] ) ) ? "" : "not " );
        }
      }

    produces the following:

    Char A is not a digit character
    Char 5 is a digit character
    Char $ is not a digit character

Classification:
    ANSI

Systems:
    All