php printf() sprintf()

<?php
    $n = 43951789;
    $u = -43951789;
    $c = 65;
    printf("%%b = %b/n", $n);
    printf("%%c = %c/n", $c);
    printf("%%d = %d/n", $n);
    printf("%%e = %e/n", $n);
    printf("%%u = %u/n", $n);
    printf("%%u = %u/n", $u);
    printf("%%f = %f/n", $n);
    printf("%%o = %o/n", $n);
    printf("%%x = %x/n", $n);
    printf("%%X = %X/n", $n);

    printf("%%+d = %+d/n", $n); //對正數指定正負號
    printf("%%+d = %+d/n", $u); //對負數指定正負號

    $s = 'monkeys';
    printf("[%10s]/n", $s);
    printf("[%-30s]/n", $s);
    printf("[%030s]/n", $s);
    printf("[%'*30s]/n", $s);
    printf("[%''30s]/n", $s);

    $num = 5;
    $location = 'tree';
    $format = "The %2/$s contains %1/$d monkeys.  // /" cannot be replaced by ',

you can have a try
           That's a nice %2/$s full of %1/$d monkeys";
    printf($format."/n", $num, $location);

    $year = 89;
    $month = 1;
    $day = 20;
    $isodate = sprintf("%04d-%02d-%02d/n", $year, $month, $day);
    var_dump($isodate);
    echo $isodate;

    $isodate = sprintf("%'#4d-%02d-%02d/n", $year, $month, $day);
    var_dump($isodate);
    echo $isodate;

?>