Recurrence in C++ exercise

I am still learn about algorithms, i have a homework. I must make an output

Sum of : 1/2 + 1/4 + 1/6 - 1/8 + 1/10 + 1/12
Result : 0.975

But output of my program

Sum of : 1/2 + 1/4 + 1/6-1/8 + 1/10 + 1/12
Result : 0.975

I dont know how to make space `negative sign`, if i use cout there will show twice negative sign.

my program

#include <iostream>
    #include <math.h>
    using namespace std;
    int main ()
    {
        int i ,sign, p, q, n;
        double x , S;
        S=0;
        cout << "Sum of :";
        for (i=1; i <= 6; i++)
        {
            if ( (i % 4 == 0) && ( i > 1 ) ) // to make condition where the number become negative
            {
                sign = -1;
    
    
            }
            if ( ( i % 4 != 0 ) && ( i > 1 ) )  // to make condition where the number become positive
            {
                sign = 1;
                cout << " + ";
            }
            if ( i == 1 ) // to prevent 1st number not show " + " symbol
            {
                sign =1;
            }
    
            p = sign*1;
            q = ( 2 * ( i - 1 ) ) + 2;
            cout << p << "/" << q;
            x = ( 1.0 * p / q );
            S = S + x;
    
        }
    
            cout << "\n" << S;
    }

I realize my program too many operation that not needed, could u help me make it more effecient ?

What I have tried:

Output of my program

Sum of : 1/2 + 1/4 + 1/6-1/8 + 1/10 + 1/12
Result : 0.975

Tags: C++