Last Character in a String

Use the following tips:

  • Trail byte ranges overlap the ASCII character set in many cases. You can safely use bytewise scans for any control characters (less than 32).

  • Consider the following line of code, which might be checking to see if the last character in a string is a backslash character:

    if ( sz[ strlen( sz ) - 1 ] == '\\' )    // Is last character a '\'?
        // . . .

    Because strlen is not MBCS-aware, it returns the number of bytes, not the number of characters, in a multibyte string. Also, note that in some code pages (932, for example), '\' (0x5c) is a valid trail byte (sz is a C string).

    One possible solution is to rewrite the code this way:

    char *pLast;
    pLast = _mbsrchr( sz, '\\' );    // find last occurrence of '\' in sz
    if ( pLast && ( *_mbsinc( pLast ) == '\0' ) )
        // . . .

    This code uses the MBCS functions _mbsrchr and _mbsinc. Because these functions are MBCS-aware, they can distinguish between a '\' character and a trail byte '\'. The code performs some action if the last character in the string is a null ('\0').

See also

MBCS Programming Tips
Character Assignment