To add two complex numbers in C program

#include <stdio.h>

struct complex
{
   int real, img;
};

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

   printf("Enter a and b where a + ib is the first complex number.\n");
   printf("a = ");
   scanf("%d", &a.real);

   printf("b = ");
   scanf("%d", &a.img);

   printf("Enter c and d where c + id is the second complex number.\n");
   printf("c = ");
   scanf("%d", &b.real);
   printf("d = ");
   scanf("%d", &b.img);

   c.real = a.real + b.real;
   c.img = a.img + b.img;

   if ( c.img >= 0 )
      printf("Sum of two complex numbers = %d + %di\n",c.real,c.img);
   else
      printf("Sum of two complex numbers = %d %di\n",c.real,c.img);
   return 0;
}