Making a square() function without x*x in C++

Question

I am self-studying C++ and the book \"Programming-Principles and Practices Using C++\" by Bjarne Stroustrup. One of the \"Try This\" asks this:

Implement square() wi

Answer 1

  //Josef.L
  //Without using multiplication operators.

int square (int a){
     int b = 0; int c =0;
    //I don't need to input value for a, because as a function it already did it for me.
    /*while(b != a){
            b ++;
        c = c + a;}*/
    for(int b = 0; b != a; b++){  //reduce the workload.
        c = c +a;
        //Interesting, for every time b is not equal to a, it will add one to its value:
        //In the same time, when it add one new c = old c + input value will repeat again.
        //Hence when be is equal to a, c which intially is 0 already add to a for a time.
        //Therefore, it is same thing as saying a * a.
    }
    return c;
}

int main(void){
    int a;
    cin >>a;
    cout <<"Square of: "<