当我运行代码时，我的开关情况不起作用，当我输入1时，它不打印情况1，等等，我尝试了每件事，但没有工作，有人能帮助我吗？当我运行代码时，我的开关情况不起作用，当我输入1时，它不打印情况1，等等，我尝试了每件事，但没有工作，有人能帮助我吗？

#include <stdio.h>
  #include <math.h>
   int main ()
  {
       int choice;
       float area;

   printf("1 for area of Square\n");
    printf(" 2 for area of Circle\n");
   printf(" 3 for finding area of rectangle\n");

    switch(choice) {

     case 1: {
         float side,area;
          printf("Enter Sides of Square");
          scanf("%f",&side);
             area=(float)side*side;
             printf("Area of Square is %f",area);
            break;
           }
  
  
         case 2: {
            float radius,area;
          printf("Enter Radius of Circle");
           scanf("%f",&radius);
            area=(float)3.14159*radius*radius;
           printf("Area of Circle %f",area);
           break;
          }
           case 3: {
           float len,breadth,area;
           printf("Enter Length and Breadth of Rectangle");
            scanf("%f %f",&len,&breadth);
              area=(float)len*breadth;
           printf("Area of Rectangle is %f",area);
            break;
              }
 
          default: {
           printf("Invalid Choice");
           break;
          }

       }
       return 0;**strong text**
      }