C++ odd-even array, infinite answer - c++

Question

This program supposed to read the number of elements and a list, and split the array for even and odd numbers, and display the number of zeros in original array.
I posted a question before for the first problem I had with this program and the answers were really helpful since this is an assignment. But now I have another problem which is every time I run the program it gave me 0 'z. and it does not stop until I close the window. I think the problem is with the count function but I was not able to diagnose the problem by myself. I added:
cout<< odd_num<< " " << even_num;
after I called count function to find out what is the problem and it gave me a really big number so whatever the error is, it is coming from this function.
So please help me! I'm sure for most of you this is very basic but I just started to learn this and really appreciate it if you can help me.
Edit: I edited this code and the only problem is an extra zero as output; look at the example output at the end.
Here is the code:
int count(const int list[], int size, int & odd , int & even)
{
int zero(0);
for (int i(0); i<size ; i++)
{
if (list[i] == 0)
{
zero++;
}
if (list[i]% 2 ==0 & list[i]!=0)
{
even++;
}
else if (list[i]% 2 ==1 & list[i]!=0)
{
odd++;
}
}
return zero;
}
void split(const int list[], int size, int list_even[], int even_num, int list_odd[], int odd_num )
{
int j(0);
int k(0);
for (int i(0); i<size; i++)
{
if(list[i]%2 == 0)
{
list_even[j]= list[i];
j++;
}
else if(list[i]%2 != 0)
{
list_odd[k]= list[i];
k++;
}
}
if (j != even_num || k != odd_num)
{
cerr << "Error.";
}
}
// function to print an array
void print_list(int array[], int length)
{
for (int a=0; a<length; a++)
{
cout <<array[a]<<" ";
}
}
And here is the sample answer:
Enter number of elements: 3
Enter list:
2
30
0
Error.Even elements:
2 30 0 0
Odd elements:
There were 1 zeros in the list
Another sample is:
Enter number of elements: 3
Enter list:
2
1
5
Error.Even elements:
2 2752708
Odd elements:
1 5 2762032 2752708
There were 0 zeros in the list

Answer 1

You did not initialize your variables try:
int zero_num(0); // number of zeros
int even_num(0);
int odd_num(0);
Try printing them out before you start using them (before this fix) and see what they are set too. :)
Fix to your count function:
// function to copy odd and even number to seperate arrays
void split(const int list[], int size, int list_even[], int even_num, int list_odd[], int odd_num )
{
int j(0);
int k(0);
for (int i(0); i<size; i++)
{
if (list[i] == 0)
{ // zeros are not considered even in the count function
// so they should not be added here.
continue;
}
else if(list[i]%2 == 0)
{
list_even[j]= list[i];
j++;
}
else if(list[i]%2 != 0)
{
list_odd[k]= list[i];
k++;
}
}
// test that we have found the right number of even and odd numbers.
if (j != even_num || k != odd_num)
{
cerr << "Error.";
}
}
And to make sure that multiple calls to the count function does not mess up your numbers make this change:
//function to count the odd and even numbers and th enumber od zeros
int count(const int list[], int size, int & odd , int & even)
{
// reset the even and odd counts before we start.
odd=0;
even=0;
int zero(0); // variable to count zeros
for (int i(0); i<size ; i++)
{
if (list[i] == 0)
{
zero++;
}
else if (list[i]% 2 == 0 )
{
even++;
}
else if (list[i]% 2 == 1 )
{
odd++;
}
}
return zero;
}
Sample output:
Enter number of elements: 5
Enter list:
1
2
5
0
0
Even elements: 2
Odd elements: 1
5
There were 2 zeros in the list
Another sample output with zeros in begining and middle:
Enter number of elements: 5
Enter list:
0
2
0
1
7
Even elements: 2
Odd elements: 1
7
There were 2 zeros in the list

Answer 2

In if condition you are using & which is bit-wise operator instead of && which is Logical AND.
See:
if (list[i]% 2 ==0 & list[i]!=0)
{
even++;
}
use && instead and see if it works, else drop me a message.

Answer 3

[Improvement] How about to write your count function like this,
int count(const int list[], int size, int & odd , int & even)
{
int zero(0);
for (int i(0); i<size; ++i)
{
if (list[i]==0)
{
++zero;
}
else
{
if (list[i]%2==0) ++even;
else ++odd;
}
}
return zero;
}