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;
        }
    }

}

}