Experiment 3-8 Output the area and circumference of a triangle (15 points)

This question requires writing a program to a、b、ccalculate and output the area and perimeter based on the three sides of the input triangle . Note: In a triangle, the sum of any two sides is greater than the third side. The formula for calculating the area of ​​a triangle:
$$area=\sqrt{s}\sqrt{(s-a)}\sqrt{(s-b)}\sqrt{(s-c)}$$
Wheres=(a+b+c)/2.

Input format:

The input is 3 positive integers, representing the 3 sides of the triangle a、b、c.

Output format:

If the input side can form a triangle, in a row, according to

area = 面积; perimeter = 周长

The output format is to retain two decimal places. Otherwise, output

These sides do not correspond to a valid triangle

Input example 1:

5 5 3

Output sample 1:

area = 7.15; perimeter = 13.00

Input example 2:

1 4 1

Output sample 2:

These sides do not correspond to a valid triangle

Code:

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

int main() {
    
    
    int a,b,c;
    scanf("%d %d %d",&a,&b,&c);
    double area,perimeter,s;
    // 能构成三角形的条件
    if (a + b > c && a + c > b && b + c > a) {
    
    
        s = (a + b + c) / 2.0;
        area = sqrt(s * (s - a) * (s - b) * (s - c));
        perimeter = 2 * s;
        printf("area = %.2lf; perimeter = %.2lf",area,perimeter);
    }else {
    
    
        printf("These sides do not correspond to a valid triangle");
    }
    return 0;
}

Submit screenshot:

Problem-solving ideas:

The difficulty of this question lies in the judgment of the triangle condition:

• The sum of any two sides is greater than the third side