// An object of type Complex is a complex number. It has // a real part (repart) and an imaginary part (impart). struct Complex { double repart, impart; }; // sum(a,b,c) sets c = a + b. void sum(const Complex& a, const Complex& b, Complex& c) { c.repart = a.repart + b.repart; c.impart = a.impart + b.impart; }