The formula for p is wrong. It's a+b+c/2 . On my screen it says a+b-c/2

include

include

include

struct triangle { int a; int b; int c; };

typedef struct triangle triangle;

int compute_area(triangle tr){ int p = (tr.a + tr.b + tr.c) / 2; int s = sqrt(p * (p - tr.a) * (p - tr.b) * (p - tr.c)); return s; }

int compare(const void *tr1, const void tr2){ int area1 = compute_area((triangle*)tr1); int area2 = compute_area((triangle)tr2); return (area1 - area2); }

void sort_by_area(triangle* tr, int n) { /** * Sort an array a of the length n */ // Sort the computed area array. qsort(tr, n, sizeof(triangle), compare); }

int main() { int n; scanf("%d", &n); triangle *tr = malloc(n * sizeof(triangle)); for (int i = 0; i < n; i++) { scanf("%d%d%d", &tr[i].a, &tr[i].b, &tr[i].c); } sort_by_area(tr, n); for (int i = 0; i < n; i++) { printf("%d %d %d\n", tr[i].a, tr[i].b, tr[i].c); }

triangle tr1 = { 54, 62, 11 };
triangle tr2 = { 31, 41, 14 };
triangle tr3 = { 20, 23, 21 };
printf("-------------- Test\n");

1. printf("%d ", compute_area(tr1)); printf("%d ", compute_area(tr2)); printf("%d ", compute_area(tr3));

return 0;

}

[ int compute_area(triangle tr){ int p = (tr.a + tr.b + tr.c) / 2; int s = sqrt(p * (p - tr.a) * (p - tr.b) * (p - tr.c)); return s; }

int compare(const void *tr1, const void tr2){ int area1 = compute_area((triangle*)tr1); int area2 = compute_area((triangle)tr2); return (area1 - area2); }

void sort_by_area(triangle* tr, int n) { /** * Sort an array a of the length n */ // Sort the computed area array. qsort(tr, n, sizeof(triangle), compare); }](https://)

Epihany. having a separate function for calculating area makes the code much simpler to understand and implement...

float calcArea (triangle tr) //func for cleaner code to calculate the area

{ float p = (tr.a + tr.b + tr.c) / 2.0;

return sqrt (p * (p - tr.a) * (p - tr.b) * (p - tr.c));

}

void sort_by_area(triangle* tr, int n)

{

for (int i = 0; i < n - 1; i++)

{

    for (int j = 0; j - n - 1; j++)

    {

        if(calcArea(tr[j]) > calcArea(tr[j+1]))

        {

            triangle temp = tr[j];

            tr[j] = tr[j+1];

            tr[j+1] = temp;

        }

    }

}

}

This is also one of the same way double area(triangle tr) { double s=(tr->a+tr->b+tr->c)/2.0; if((tr->a+tr->b)>tr->c&&(tr->b+tr->c)>tr->a&&(tr->a+tr->c)>tr->b) { double area=sqrt(s(s-tr->a)(s-tr->b)(s-tr->c)); return area;

}
return 0;

}

void sort_by_area(triangle* tr, int n) {

double arr[n];
for(int i=0;i<n;i++)
{
     arr[i]=area(&tr[i]);
}
for(int i=0;i<n;i++)
{
    for(int j=0;j<i;j++)
    {
        if (j == i)
        {
          arr[j] = arr[i]; 
        }
        if(arr[j]>arr[i])
        {
            double temp_1=arr[j];
            arr[j]=arr[i];
            arr[i]=temp_1;
            triangle temp=tr[j];
            tr[j]=tr[i];
            tr[i]=temp;
        }
    }

}

}