[PHP Example] Several methods to implement the multiplication table (three loops, four angles, and one recursion)

one thousand four hundred and twenty-one
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December 14, 2017 00:15:26 PHP technology comment nine hundred and eighty-one Reading mode

Implementing the multiplication table in PHP is a practical problem encountered in the interview. Today, I will summarize it. It's nothing for a veteran. It's easy. But for a novice like me, writing in different ways is quite a training of logical thinking.

<? php
//1、 Use the for loop to print the 99 multiplication table:
for ( $j =1; $j <=9; $j ++) {
for ( $i =1; $i <= $j ; $i ++) {
echo "{$i}x{$j}=" .( $i * $j ). " " ;
}
echo "<br />" ;
}
//2、 Use the while loop to print the nine nine multiplication table
$j = 1;
while ( $j <=9){
$i = 1;
while ( $i <= $j ){
echo "{$i}x{$j}=" .( $i * $j ). " " ;
$i ++;
}
echo "<br />" ;
$j ++;
}
//3、 Use do while loop to print 99 multiplication table
$j = 1;
do {
$i = 1;
do {
echo "{$i}x{$j}=" .( $i * $j ). " " ;
$i ++;
} while ( $i <= $j );
echo "<br />" ;
$j ++;
} while ( $j <=9);
//Now use the for loop to output the multiplication table in table form
//Angle 1: (the most common conventional writing method)
echo "<table border='1'>" ;
for ( $j =1; $j <=9; $j ++){
echo "<tr>" ;
for ( $i =1; $i <= $j ; $i ++){
echo "<td>{$i}*{$j}=" .( $i * $j ). "</td>" ;
}
echo "</tr>" ;
}
echo "</table>" ;
//Angle 2: (X axis symmetry with conventional writing)
echo "<table border='1'>" ;
for ( $j =9; $j >=1; $j --){
echo "<tr>" ;
for ( $i =1; $i <= $j ; $i ++){
echo "<td>{$i}*{$j}=" .( $i * $j ). "</td>" ;
}
echo "</tr>" ;
}
echo "</table>" ;
//Angle 3: (symmetrical to the Y axis of angle 2)
echo "<table border='1'>" ;
for ( $j =9; $j >=1; $j --){
echo "<tr>" ;
for ( $z =0; $z <9- $j ; $z ++){
echo "<td> </td>" ;
}
for ( $i =1; $i <= $j ; $i ++){
echo "<td>{$i}*{$j}=" .( $i * $j ). "</td>" ;
}
echo "</tr>" ;
}
echo "</table>" ;
//Angle 4: (Y axis symmetry with conventional writing)
echo "<table border='1'>" ;
for ( $j =1; $j <=9; $j ++){
echo "<tr>" ;
for ( $z =0; $z <9- $j ; $z ++){
echo "<td> </td>" ;
}
for ( $i = $j ; $i >=1; $i --){
echo "<td>{$i}*{$j}=" .( $i * $j ). "</td>" ;
}
echo "</tr>" ;
}
echo "</table>" ;
//Recursive writing
//@ param int: $i number
//@ param int: $k layers
function rideNum( $i =1, $k =1){
if ( $i >= 10 || $k >= 10){ exit ;}
echo $i .'x'. $k .'='. $i * $k .' ';
#The number of outer layers is the same as that of the number, and the next page is broken
if ( $i == $k ){
echo '<br/>';
rideNum(1, $k +1);
}
#If the number is not enough, continue+1, and the Bank will continue to output
rideNum( $i +1, $k );
}
rideNum(1,1);

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