What's the point of the NOT operator?

c++

Solution

Okay, you want to divide the sum of two numbers to a third one, so you can do this if the third number is not zero.

    #include <iostream>
    using namespace std;
    int main()
   {
    int a,b,c,sum;
    cin >> a >> b >> c;
    sum = a+b;
    if (c!=0) //which is equivalent to if(!c)
    cout << sum/c;
   }

I used an easy example in order to understand it quickly. Is everything okay now? Regards and good luck with your study.

Problem

Currently checking out C++ using this tutorial. It explains what the `! NOT` operator is, kind of, but I don't think I fully understand why I'd ever want to use it. Can someone please explain?

Original source