<math.h> The area of a triangle given 3 sides

main.c

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

int main() {
    double s1, s2, s3, p, area;
    printf("Enter the lengths of 3 sides of a triangle: ");
    scanf("%lf %lf %lf", &s1, &s2, &s3);
    p = (s1 + s2 + s3) / 2;
    area = sqrt(p*(p-s1)*(p-s2)*(p-s3));
    printf("The area of the triangle is %.2lf\n", area);
    return (0);
}

output.txt

Enter the lengths of 3 sides of a triangle: 8 11 5
The area of the triangle is 18.33

Program ended with exit code: 0