PHP嵌套while循环

Question

I tried to do a while inside a while to print a multiplication table like,

1  2  3  4  5
2  4  6  8 10
3  6  9 12 15
4  8 12 16 20
5 10 15 20 25

But I got only 1, 2, 3, 4, 5.

Code:

$i = 1;
$x = 1;
while($i <= 5){
   while($x <= 5){
     echo $i * $x;
     $x++;
   }
   echo "<br>";
   $i++;
}

Answer 1

You need to reset $x, so:

$i = 1;
$x = 1;
while($i <= 5){
    while($x <= 5){
        echo $i * $x;
        $x++;
    }
    $x = 1; // added this line
    echo "<br>";
    $i++;
}

Output:

12345
246810
3691215
48121620
510152025

You can then do what ever you want to format it.

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More elabrate explanation:

• First run:

It enters both outer and inner loops, showing the desired output for the first line. You end up with $i = 2 and $x = 6.

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• Second run:

Since $i is 2, it doesn't leave the outer loop, but $x is 6, so it doesn't enter the inner loop again.

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• Last* run:

It then keeps adding 1 to $i until it doesn't match the outer loop condition anymore and leaves you with that unwanted result.