circle ,rectangle,square and triangle using switch case

/*write a program to calculate the area of circle ,rectangle,square and triangle in one program with using switch case /*

#include
#include
void main()
{
int a=0,b,pi=3.14,r,h,n;
clrscr();
printf("enter r:");
scanf("%d",&r);
printf("enter b:");
scanf("%d",&b);
printf("enter h:");
scanf("%d",&h);
printf("\nenter 1 for circle\nenter 2 for square\nenter 3 for rectangle\nenter 4 for triangle\n");
printf("enter choice:");
scanf("%d",&n);

switch (n)
{
case 1:
a=pi*r*r;
printf("area of circle is %d",a);
break;
case 2:
a=4*b;
printf("area of square is %d",a);
break;
case 3:
a=2*b*h;
printf("area of rectangle is %d",a);
break;
case 4:
a=(b/2)*h;
printf("area of triangle is %d",a);
break;
default:
printf("bug");
break;
}
getch();
}