// Online C compiler to run C program online
#include <stdio.h>
#include <math.h>
int main() {
    float a,b,c,s,area;
    int n;
    printf("CHOOSE THE ACTION TO PERFORM.....\n");
    printf("1.RECTANGLE\n");
    printf("2.SQUARE\n");
    printf("3.CIRCLE\n");
    printf("4.TRIANGLE\n");
    scanf("%d\n",&n);
    
    switch(n) {
        case 1: printf("Enter L&B of Rectangle...\n");
                scanf("%d%d",&a,&b);
                area = a*b;
                printf("Area=%f",area);
                break;
                
        case 2: printf("Enter side of Square...\n");
                scanf("%f",&a);
                area = a*a;
                printf("Area=%f",area);
                break;
                
        case 3: printf("Enter Radius of Circle...\n");
                scanf("%f",&a);
                area = 3.14*a*a;
                printf("Area=%f",area);
                break;
                
        case 4: printf("Enter 3 sides of Triangle ...\n");
                scanf("%f%f%f",&a,&b,&c);
                s=(a+b+c)/2;
                area = sqrt(s*(s-a)*(s-b)*(s-c));
                printf("Area=%f",area);
                break;        
    }

    return 0;
}