poj 1658 Eva's Problem

#include <iostream>
using namespace std;

int main()
{
int tc, num[5], tmp[3];
cin >> tc;
while (tc--)
{
cin >> num[0] >> num[1] >> num[2] >> num[3];
tmp[0] = num[1] - num[0];
tmp[1] = num[2] - num[1];
tmp[2] = num[3] - num[2];
if (tmp[0] == tmp[1] && tmp[1] == tmp[2])
{
num[4] = num[3] + tmp[0];
for (int i = 0; i < 5; i++)
{
if (i)
cout << " ";
cout << num[i];
}
cout << endl;
}
else
{
num[4] = (num[3] * num[3])/num[2];
for (int i = 0; i < 5; i++)
{
if (i)
cout << " ";
cout << num[i];
}
cout << endl;
}
}

system("pause");
}