# C++ program to add two complex numbers using class

In this article, we will write a program to add two complex numbers (a1 + ib1) and (a2 + ib2) using class.

For example

Input: 4 + i5 and 8 + i9

Here a1= 4 and a2 = 8. On adding a1 and a2, we get (8 + 4) = 12

Further, b1 = 5 and b2 = 9. On adding b1 and b2, we get (5 + 9) = 14

Output: 9 + i14

Input: 2 + i7 and 10 + i6

Here a1= 2 and a2 = 10. On adding a1 and a2, we get (2 + 10) = 12

Further, b1 = 7 and b2 =6. On adding b1 and b2, we get (7 + 6) = 13

Output: 12 + i13

## Class construction

At first, we will create a class for complex numbers. The observation shows that there is a real number(a1) and an imaginary number(b1) in a complex number.

We need two data members to represent the complex numbers.

Below is the class structure:

## Constructors

Two constructors will be made to initialize the data members of the class Complex.

• Non - Parameterized constructor

We need a non - parameterized constructor to initialize the default values of the data members to zero.

Below is the structure of non-parameterized constructor

• Parameterized constructor

We need a non-parameterized constructor to initialize the data members to the value passed by the main function.

Below is the structure of parameterized constructor

## Algorithm

For adding two complex numbers, we will make two objects of the Complex class and initialize them with the values. After that, we will make a third object that will store the result.

C++ code

Output

```Complex number 1 : 4 + i5
Complex number 2 : 8 + i9
Sum of complex number : 12 + i14

Complex number 1 : 2 + i7
Complex number 2 : 10 + i6
Sum of complex number : 12 + i13

Time complexity
The time complexity is O(1) as we have to call the function addComplexNumber() to add the two complex numbers.
```

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