Question

I have following code to divide one number recursively by another number:

#include <iostream>
using namespace std;

int divide(int number,int dividend){
    int answer=0;
    if (number>dividend  || number==dividend ){
        answer+=1;
        return  divide(number-dividend,dividend);
    }
    return answer;     
}

int main(){    
    cout<<divide(20,5)<<endl;
    return 0;
}

but unfortunately I get zero as answer. Do you see what is wrong?

Answer 1

Answer is a local variable. When you run this code, the first call to divide creates an instance of the answer variable, sets it to 0, and then increments it to 1. Then, when you recursively call divide again, it creates a brand new instance of the answer variable, sets that instance to 0, and then increments that instance to 1.

In your final call to divide, it creates a brand new instance of the answer variable, sets that instance to 0, but since now number<=dividend it doesn’t increment it, and it returns that instance of answer which is 0.