Hey friends! Give me defination of second loop on my below description and reply me why its sum is 20.

Question

using namespace std;

int main() {
int s=0, n=4;
cin >> n;
for(int i=1; i<=n; i++) {
for(int j=1; j<=i; j++) {
s += j;
}
}
cout << s;
return 0;
}

//output is 20 but why and how?

Answer 1

add this right under s += j; so you can see whats going on
cout << s << i << j;