Summing pairs of fractions S24486

Write a program to sum a sequence of pairs of fractions. To practice top-down design, the program should be the result of completing the lines of code outlined below.

    
   ....
   
   struct Rational {
        int num; // numerator
        int den; // denominator
    };
    

    //pre: ....
    //post: ....
    int gcd_euclides(...)

    //pre:---
    //post: returns r in simplified form
    Rational simplify(Rational r)
 
    //....
    void write_rational(Rational r) {
        if (r.num == 0) cout << "0";
        else if (r.den == 1) cout << r.num;
        else cout << r.num << "/" << r.den;
    }

    ....
    .... 
    ....

    int main() {
        Rational rat1, rat2, total={0,1};
        while (read_pair_rationals(....)) {
            Rational sum = sum_and_simp(....);
            write_sum(....);
            ...
        }
        write_result(total);
    }

Input

Input consists of sequence of lines. Each line contains four integers $a, b, c, d$ representing fractions $\frac{a}{b}$ and $\frac{c}{d}$. It holds $b \neq 0$ and $d \neq 0$

Output

Summation of the pairs of fractions $\frac{a}{b} + \frac{c}{d}$ (one per line) and the final sum of all of them at the end. The result fractions need to be simplified: numerator and denominator have no common factors, and the denominator is positive. If a fraction is $\frac{0}{n}$ you should write only $0$. If the fraction is $\frac{n}{1}$ you should write only $n$. Follow the format of examples below.