Answer 1

You have the right idea, though your function never actually returns a value so would cause a compiler error. You'd also have an infinite loop if it did, as well as a few other issues.

Here's how I'd do it (you can probably figure out where you went wrong with the code below):
http://code.sololearn.com/c379CafwFEnE/

#include <iostream>
using namespace std;
int numbers[]{ 8, 2, 5, 1, 22, 63, 45, 23 };
int findHighestNumber(int arr[], int arraySize, int highest = 0, int index = 0)
{
if (index == arraySize) {
return highest;
}
else {
if (arr[index] > highest) {
highest = arr[index];
}
return findHighestNumber(arr, arraySize, highest, index + 1);
}
}
int main() {
int arraySize = sizeof(numbers) / sizeof(numbers[0]);
cout << "Highest number in array: " << findHighestNumber(numbers, arraySize) << endl;
return 0;
}