C++ :: Read 50 Integers From A File And Sum Them Together

You are to create a program that will read 50 integers from a file and sum them together. Output this sum to an output file. You will also output (to the file) how many numbers were odd, and how many were even (zeros may be considered even). Your program MUST employ a while loop to read the values from the file.

The while loop should check for TWO things (what are they?). Hint: you know you need to read 50 numbers, but for correct file processing, what else should you check for? Your grade will be based on whether or not you correctly identify both conditions to be used in the while loop.

Code:
#include <iostream> // Preprocessor directive for cin and cout
#include <fstream>
using namespace std;
int main () {
// Declaring variables
ifstream num_list;
int number(0), even(0), odd(0), count(0);

[Code] .....

I am getting error: no match for 'operator+=' in 'sum += num_list' .....