multi.cpp

#include <iostream>
#include <cmath>
using namespace std;
int multi(int x, int y){
  if(y==0)
    return 0;
  int z = multi(x, y/2);
  if(y%2 == 0)
    return 2*z;
  else
    return x+2*z;

}
int display(int x){
  if(x == 0)
    return 0;
  cout<< display(x-1)<<",";
  if(x%2 == 0)
    return x;
  else
    return display(x+1);
}

int main(){
  cout<<multi(10,10)<<endl;
  display(100);

  return 0;
}