A brief discussion on the sixth bullet of PHP - using for loop to output the multiplication table_PHP tutorial

Last time http://www.BkJia.com/kf/201204/128751.html I told you about the Nine Yang Magic of paging. I don’t know how well you master it. I hope it can help you!

These days I found that some children's shoes still have some problems in the loop of outputting the multiplication table. Today I will explain it to you in detail...

First let’s look at the code:
for($i=1;$i<=9;$i++){
for($j=1;$j<=$i;$j++){
echo "$j x $i = ".$j*$i." ";
}
echo "
";
}
?>
Output result:

Okay, let’s analyze it step by step:

We call the outermost loop a "trip":

First trip:

$i is 1, satisfying $i <= 9,

And the inner loop $j satisfies $j <= $i, output 1 x 1 = 1

$j increases by 1, no longer satisfies $j <=$i, and no longer outputs

Output "
" line break,

$i increments itself by 2

This trip is over.

Second trip:

$i is 2, satisfies $i < = 9, and starts executing the second loop

At this time, the condition of the inner loop becomes:

for($j =1 ; $j < = 2 ; $j++){
........
}

The inner loop outputs twice, respectively:

1 x 2 = 2 and 2 x 2 = 4

Similarly, when $j in the inner loop increases to 3, the inner loop will no longer be executed

Output "
";

$i increments to 3

This trip is over!

Third trip:

Same as above....

And so on:

Until the ninth trip:

At this time $i has been increased to 9

$i <= 9 still holds

Execute the ninth inner loop:

At this time, the inner loop becomes

for($j=1 ; $j <=9 ; $j++){
.......
}

Loop and execute the code in the loop body 9 times,

are respectively

1 x 9 = 1 2 x 9 =18..........9 x 9 = 81

That is the last line of the result

At this time $j no longer satisfies $j<=9, and the inner loop execution ends

Output "
"

$i increases to 10

This trip is over.

By the tenth time, $i is already 10 and no longer satisfies $i<=9. At this time, this cycle will no longer be executed.
Finally, the multiplication table shown in the picture above is output.

How about it? I don’t know if you understand it. If you understand it, you can try to output the multiplication table in reverse! The principle is the same!



Author zdrjlamp