Complex numbers ADD/MUL ~ Bachelor Zone

Complex numbers ADD/MUL

/* Write a C program that uses functions to perform the following operations:
i) Reading a complex number
ii) Writing a complex number
iii) Addition of two complex numbers
iv) Multiplication of two complex numbers
(Note: represent complex number using a structure.) */

#include<stdio.h>
#include<math.h>

void arithmetic(int opern);

struct comp
{
   double realpart;
   double imgpart;
};

void main()
{
   int opern;
   clrscr();
   printf("\n\n \t\t\t***** MAIN MENU *****");
   printf("\n\n Select your option: \n 1 : ADD\n 2 : MULTIPLY\n 0 : EXIT \n\n\t\t Enter your Option [ ]\b\b");

   scanf("%d",&opern);

   switch(opern)
   {
case 0:
exit(0);
case 1:
case 2:
arithmetic(opern);
default:
main();
   }

}

void arithmetic(int opern)
{

   struct comp w1, w2, w;

   printf("\n Enter two Complex Numbers (x+iy):\n Real Part of First Number:");
   scanf("%lf",&w1.realpart);
   printf("\n Imaginary Part of First Number:");
   scanf("%lf",&w1.imgpart);
   printf("\n Real Part of Second Number:");
   scanf("%lf",&w2.realpart);
   printf("\n Imaginary Part of Second Number:");
   scanf("%lf",&w2.imgpart);

   switch(opern)
   {

   /*addition of complex number*/
   case 1:
w.realpart = w1.realpart+w2.realpart;
w.imgpart = w1.imgpart+w2.imgpart;
break;

   /*multiplication of complex number*/
   case 2:
w.realpart=(w1.realpart*w2.realpart)-(w1.imgpart*w2.imgpart);
w.imgpart=(w1.realpart*w2.imgpart)+(w1.imgpart*w2.realpart);
break;
   }

   if (w.imgpart>0)
printf("\n Answer = %lf+%lfi",w.realpart,w.imgpart);
   else
printf("\n Answer = %lf%lfi",w.realpart,w.imgpart);
   getch();
   main();
}