hey im trying to do a quick mod function, i know % exists but this will have other applications... Basically the main issues is when you return "num" it is a different value than if you look at num before it is returned...

Any ideas? thanks in advance

int mod(int num, int num2)
{
  if (num < num2)
    return num;
  mod(num-num2,num2);
}
Member Avatar for r.stiltskin

Can you explain the problem more clearly? How/where are you looking at num?

Can you explain the problem more clearly? How/where are you looking at num?

Here is an example... why are num and ans not equal?

#include <iostream>
using namespace std;

int mod(int&,int&);

int main()
{
  int num = 2001,
      num2 = 5;
  int ans = mod(num,num2);
  cout << "The number returned by mod function = " << ans  << endl
       << "The number passed by num in mod function = " << num << endl
       << num << " != " << ans << endl;
  system("PAUSE");
  return 0;
}

int mod(int &num, int &num2)      
{
  if (num < num2)
    return num;
  num -= num2;
  mod(num,num2);
}

change :

int mod(int &num, int &num2)

to

int mod(int num, int num2)

So it works with the copy of num1 and num2 and not it indirectly.

2001 % 5 = 1 .... i was showing you that "num" was correct before returned... this has nothing to do with passing by reference... the returned number of function mod should be 1... not 923472947 << some random number. try running that code... you will see

Try to return some value. Compiling with -Wall is helpfull.

Member Avatar for r.stiltskin

Sorry, I still don't see what your problem is. You have changed the code but I'm not sure why. Originally your function signature was:

int mod(int num, int num2)

which is correct and in your example program returns the value 1.

But in post #3 you changed it to

int mod(int &num, int &num2)

This still runs correctly & returns the value 1, and it also modifies the value of the original argument num in the calling function. I just don't see why you would want to do that since you lose the original value apparently without gaining anything.

But either way, what is your question?

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