Simple Recursion (Multiplying by using Addition)
 

Hello all,

My objective is simple. I have to take in 2 positive integers and multiply them by using addition. This is a recursive problem.

Example of Output:


Please enter 2 positive integers to multiply:

4 2

4 * 2 = 8


The problem is whenever the user types in both numbers, the program window just disappears.

To receive my result, I am suppose to use something like:

x + multiply(x,--y);


Please help me with this...Thank you

#include <iostream>



using namespace std;



int multiply(int x, int y);



int main()

{

    

int x;

int y;          

    



cout<<"Please enter 2 positive integers to multiply"<<endl;

cin>>x;

cin>>y;



cout<<x<<" * "<<y<<" = "<<multiply(x,--y)<<endl;



    

system ("PAUSE");

return 0;

}





int multiply(int x, int y)

{





if (x == 0)

{

return 0;

}



if (x == 1)

{    

return x;

}



if (x > 1)



{

return (x + multiply(x,--y));

}



}

Re: Simple Recursion (Multiplying by using Addition)
 

You test x, and only change y

Re: Simple Recursion (Multiplying by using Addition)
 

As long as you are decrementing y you should put y in your base cases checks, otherwise

multiply(2, wathever);

would result in *endless* recursion.

EDIT: Sorry, Salem beated me in speed.