Complex Numbers in C++

In this section we will see how to create and use complex numbers in C++. We can create complex number class in C++, that can hold the real and imaginary part of the complex number as member elements. There will be some member functions that are used to handle this class.

In this example we are creating one complex type class, a function to display the complex number into correct format. Two additional methods to add and subtract two complex numbers etc.

Example

 Live Demo

#include<iostream>
using namespace std;
class complex {
   int real, img;
   public:
      complex() {
         //default constructor to initialize complex number to 0+0i
         real = 0; img = 0;
      }
      complex(int r, int i) {
         //parameterized constructor to initialize complex number.
         real = r; img = i;
      }
      void set();
      void get();
      void display();
      friend complex add(complex, complex);
      friend complex sub(complex, complex);
};
void complex::set() {
   cout << "Enter Real part: ";
   cin >> real;
   cout << "Enter Imaginary Part: ";
   cin >> img;
}
void complex::get() {
   cout << "The complex number is: "<< real << "+" << img << "i" << endl;
}
void complex::display() {
   if(img < 0)
      if(img == -1)
         cout << "The complex number is: "<< real << "-i" << endl;
      else
         cout << "The complex number is: "<< real << img << "i" << endl;
      else
         if(img == 1)
            cout << "The complex number is: "<< real << " + i"<< endl;
         else
            cout << "The complex number is: "<< real << " + " << img << "i" <<
   endl;
}
complex add(complex c1, complex c2) {
   complex res;
   res.real = c1.real + c2.real;//addition for real part
   res.img = c1.img + c2.img;//addition for imaginary part
   return res;//the result after addition
}
complex sub(complex c1, complex c2) {
   complex res;
   res.real = c1.real - c2.real;//subtraction for real part
   res.img = c1.img - c2.img;//subtraction for imaginary part
   return res;//the result after subtraction
}
main() {
   complex n1(3, 2), n2(4, -3);
   complex result;
   result = add(n1,n2);
   result.display();
   result = sub(n1,n2);
   result.display();
}

Output

The complex number is: 7-i
The complex number is: -1 + 5i