C++ Having an issue with filling an array - c++

Question

I'm having an issue with my C++ code that involves receiving input from the user and filling an array based on that input. For my function fillArray(), I need a way to read all inputs from one line and to fill an array with those inputs until the user inputs -1 at the end, something other than a positive integer, or exceeds the threshold of 20 elements.
For example, if I input
1 2 3 4 5 6 -1 on one line, I want the displayArray() function to output 1 2 3 4 5 6, or if i write 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21, I want displayArray() to output 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20.
It seems that whenever I input -1 at the end, displayArray() outputs something like
1 2 3 4 5 6 94837 or some arbitrarily big number. If somebody could help me out with this, I'd appreciate it, here's my code:
#include <iostream>
using namespace std;
const int CAPACITY = 20;
void displayArray(int array[], int numElements)
{
for (int i = 0; i < numElements; i++)
cout << array[i] << " ";
cout << endl;
}
void fillArray(int array[], int& numElements)
{
int arrayPosition = 0;
int testArrayPosition = 0;
int testArray[CAPACITY];
bool continueReading = true;
cout << "Enter a list of up to 20 integers or -1 to end the list";
do
{
cin >> valueEntered;
if (valueEntered == -1)
{
continueReading = false;
} else if (valueEntered != -1) {
array[arrayPosition] = valueEntered;
arrayPosition++;
}
} while ((continueReading==true) || (arrayPosition >= CAPACITY));
numElements = (arrayPosition+1);
}
int main()
{
int array[CAPACITY];
int numArrayElements = 0;
fillArray(array, numArrayElements);
displayArray(array, numArrayElements);
cout << "NumArrayElements: " << numArrayElements << endl;
}

Answer 1

The code you posted does not compile. You refer in several places to a variable valueEntered without ever having declared it.
Also, the following construct does not make sense:
if (valueEntered == -1)
{
[...]
}
else if (valueEntered != -1)
{
[...]
Since the condition expression of the second if statement is the exact negation of the condition expression of the first statement, the second if statement is superfluous and can be removed, like this:
if (valueEntered == -1)
{
[...]
}
else
{
[...]
However, since you stated in your question that anything else than a positive integer (not just -1) should cause your program to end, you will want to change that part of your program to the following:
if (valueEntered <= 0)
{
continueReading = false;
}
else
{
array[arrayPosition] = valueEntered;
arrayPosition++;
}
Also, as has already been stated by someone else in the comments section, the line
while ((continueReading==true) || (arrayPosition >= CAPACITY));
should be changed to
while ( continueReading && arrayPosition < CAPACITY )
and the line
numElements = (arrayPosition+1);
should be changed to
numElements = arrayPosition;