## Reverse an integer using math operations.

Build up a new number m by multiplying by 10 and dividing the original number n by 10 until n is 0. The digit in the ‘ones’ position is taken from the original and added to the new number at each iteration.

```c
int reverse(int n) {
    int m = 0;
    while (n) {
        int r = n % 10;
        m = m * 10 + r;
        n = n / 10;
    }
    return m;
}
```