php中数字转换成货币格式实现代码

function format_money( $STR )
{
        if ( $STR == "" )
        {
                return "";
        }
        if ( $STR == ".00" )
        {
                return "0.00";
        }
        $TOK = strtok( $STR, "." );
        if ( strcmp( $STR, $TOK ) == "0" )
        {
                $STR .= ".00";
        }
        else
        {
                $TOK = strtok( "." );
                $I = 1;
                for ( ;    $I <= 2 - strlen( $TOK );    ++$I    )
                {
                        $STR .= "0";
                }
        }
        if ( substr( $STR, 0, 1 ) == "." )
        {
                $STR = "0".$STR;
        }
        return $STR;
}