SWITCH CASE (AREA)

//example of switch case
#include<stdio.h>
void main (void)
{

int select;
float pi,r,area,w,h,b,a,radians;
pi = 3.142;

printf("*********programs to calculate area rectangle**************\n");
printf("*                please select an option                  *\n");
printf("*                                                         *\n");
printf("*                     1.Triangular                        *\n");
printf("*                     2.Circle                            *\n");
printf("*                     3.Square                            *\n");
printf("*                     4.Ellipse                           *\n");
printf("*                     5.Trapezoid                         *\n");
printf("*                     6.Sector                            *\n");
printf("*                     7.Exit                              *\n");
printf("***********************************************************\n");

scanf("\n%d",&select);
start:// for reboot


   switch(select)
   {
      case 1:
      printf("calculate the area of triangular\n");
  //printf("calculate the area of triangular");
      printf("key in the base for calculation = ");
  scanf("\n%f",&b);
  printf("key in the height for calculation = ");
  scanf("\n%f",&h);
  area = 0.5*(b*h);
  goto answer;
  break;

  case 2:
      printf("program to calculate circle\n");
      printf("key in the radius for calculation = ");
  scanf("\n%f",&r);
  area = pi*(r*r);
  goto answer;
  break;

  case 3:
      printf("program to calculate square\n");
      printf("key in the length of side for calculation = ");
  scanf("\n%f",&a);
  area = a*a;
  goto answer;
  break;

  case 4:
      printf("program to calculate ellipse\n");
      printf("key in the length of side for calculation = ");
  scanf("\n%f",&a);
  printf("key in the base for calculation = ");
  scanf("\n%f",&b);
  area = pi*a*b;
  goto answer;
  break;

  case 5:
      printf("program to calculate trapezoid\n");
      printf("key in the length of side for calculation = ");
  scanf("\n%f",&a);
  printf("key in the base for calculation = ");
  scanf("\n%f",&b);
  printf("key in the height for calculation = ");
  scanf("\n%f",&h);
  area = 0.5*(a+b)*h;
  goto answer;
  break;

  case 6:
      printf("program to calculate sector\n");
      printf("key in the radius for calculation = ");
  scanf("\n%f",&r);
  printf("key in the angle in radians for calculation = ");
  scanf("\n%f",&radians);
  area = 0.5*(r*r)*radians;
  goto answer;
  break;

  case 7:
  goto exit;
  break;

      default:
      printf("wrong case selected!!!");
  goto exit;
   }

answer:printf("the area is = %f\n",area);
goto start;
exit:;
}