This C Program adds two complex numbers.A complex number is a number that can be put in the form a + bi, where a and b are real numbers and i is called the imaginary unit, where i2 = -1. In this expression, a is called the real part and b the imaginary part of the complex number.
Here is source code of the C Program to add two complex numbers. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

/*
* C Program to Add two Complex Numbers
*/
#include <stdio.h>

struct complex
{
int realpart, imaginary;
};

main()
{
struct complex a, b, c;

printf("Enter value of a and b complex number a + ib.\n");
printf("value of complex number a is = ");
scanf("%d", &a.realpart);
printf("value of complex number b is = ");
scanf("%d", &a.imaginary);
printf("Enter value of c and d complex number c + id.\n");
printf("value of complex number c is = ");
scanf("%d", &b.realpart);
printf("value of complex number d is = ");
scanf("%d", &b.imaginary);
c.realpart = a.realpart + b.realpart;
c.imaginary = a.imaginary + b.imaginary;
if (c.imaginary >= 0)
printf("complex numbers sum is = %d + %di\n", c.realpart, c.imaginary);
else
printf("complex numbers sum = %d %di\n", c.realpart, c.imaginary);
return 0;
}

$ cc pgm55.c
$ a.out
Enter value of a and b complex number a + ib.
value of complex number a is = 10
value of complex number b is = 12
Enter value of c and d complex number c + id.
value of complex number c is = 15
value of complex number d is = 22
complex numbers sum is = 25 + 34i