# PHP Program - Reverse digits of a given Integer

In PHP, the reverse of a given integer can be found out by using below mentioned methods.

### Method 1: Using iteration

The method involves the following steps:

```Input: MyNum
Step 1: Initialize the RevNum = 0
Step 2: Iterate over MyNum while it is greater than zero.
Step 2a: Calculate remainder of MuNum / 10
Step 2b: Update RevNum by RevNum * 10 + remainder
Step 2c: Update MyNum by (int)MyNum / 10
Step 3: Return RevNum
```

### Example:

```Input: 564

RevNum: 0
Iteration 1:
Remainder: 564 % 10 = 4
RevNum: 0 * 10 + 4 = 4
MyNum: 564 / 10 = 56

Iteration 2:
Remainder: 56 % 10 = 6
RevNum: 4 * 10 + 6 = 46
MyNum: 56 / 10 = 5

Iteration 3:
Remainder: 5 % 10 = 5
RevNum: 46 * 10 + 5 = 465
MyNum: 5 / 10 = 0

return RevNum = 465
```

The below block of code shows the implementation of above concept:

```<?php
function reverse(\$MyNum){
\$RevNum = 0;
\$remainder;

while(\$MyNum > 1){
\$remainder = \$MyNum % 10;
\$MyNum = (int)\$MyNum / 10;
\$RevNum = \$RevNum * 10 + \$remainder;
}
return \$RevNum;
}

\$x = 1285;
\$y = 4567;
echo "Reverse of \$x is: ".reverse(\$x);
echo "\nReverse of \$y is: ".reverse(\$y);
?>
```

The above code will give the following output:

```Reverse of 1285 is: 5821
Reverse of 4567 is: 7654
```

### Method 2: Using Recursion

The above result can also be achieved using recursive function. Consider the example below:

```<?php
\$RevNum = 0;
\$base = 1;

function reverse(\$MyNum){
global \$RevNum;
global \$base;

if(\$MyNum > 1){
reverse((int)\$MyNum/10);
\$RevNum += \$MyNum % 10 * \$base;
\$base *= 10;
}
return \$RevNum;
}

\$x = 7902;
echo "Reverse of \$x is: ".reverse(\$x);
?>
```

The above code will give the following output:

```Reverse of 7902 is: 2097
```

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