return Number / Number;
Number / Number is 1 unless Number is 0 in which case it's undefined.

To get the square root of a number you can use the sqrt function in <cmath>
Code:
#include <cmath>
#include <iostream>

using namespace std;

int main()
{
    double n = 9.0;
    cout << "sqrt(" << n << ") = " << sqrt(n) <<'\n';
}