Q:

No errors but nothing happens when I run (C++)

Simple program that reads 6 numbers from keyboard and returns the sum of all the even numbers. But when I run this, it doesn't print anything and just quits.
What am I missing here? (I know vector would be better but I'm practicing for finals and this is an old finals question that specified using arrays).
#include <iostream>

using namespace std;

void readNumbers();
void sumOfEven(int arr[6]);

int main(){
    void readNumbers();
    return 0;
}

void readNumbers(){
    int myArray[6];
    cout << "Enter 6 numbers:" << endl;
    for(int i = 0; i < 6; i++){
        cin >> myArray[i];
    }
    sumOfEven(myArray);
}

void sumOfEven(int arr[6]){
    int sum = 0;
    for(int i = 0; i <= 6; i++){
        if(arr[i] % 2 == 0)
            sum = sum + arr[i];
    }
    cout << "Sum of even numbers: " << sum;
}

A:

In main there is a function declaration instead of a function call
int main(){
    void readNumbers();
    ^^^^^^^^^^^^^^^^^
    return 0;
}

You should write
int main(){
    readNumbers();
    ^^^^^^^^^^^^^^
    return 0;
}

The second problem is that you use incorrect indices in the loop
for(int i = 0; i <= 6; i++){
               ^^^^^^^

There must be
for(int i = 0; i < 6; i++){
               ^^^^^

