Three examples C language

Title: An integer plus 100 after it is a perfect square, plus 168 is a perfect square, what is the number is how much?

Program analysis:

Assuming that the number x.

1, then: x + 100 = n2, x + 100 + 168 = m2

2, calculation equation: m2 - n2 = (m + n) (m - n) = 168

3, is provided: m + n = i, m - n = j, i * j = 168, i and j is an even number at least one

4, can be obtained: m = (i + j) / 2, n = (i - j) / 2, i and j are either both even or both odd.

5, 3, and 4 derived from know, I and j are both an even number greater than or equal to 2.

6, since i * j = 168, j> = 2, then 1 <i <168/2 + 1.

7, all numbers next cycle i can be calculated.

Specific achieve the following:

#include <stdio.h>
int main (void)
{
int  i, j, m, n, x;
for (i = 2; i <= 168 / 2; i=i+2)
{
    if (168 % i == 0)
    {
        j = 168 / i;
        if ( i > j && (i + j) % 2 == 0)
        {
            m = (i + j) / 2;
            n = (i - j) / 2;
            x = n * n - 100;
            printf ("%d + 100 = %d * %d\n", x, n, n);
            printf ("%d + 268 = %d * %d\n", x, m, m);
        }
    }
}
return 0;
}