Function template: sum and average of array

#include <iostream>
using namespace std;

template <class T>
T sum(T arr[], int n) {
    T total = 0;
    for (int i = 0; i < n; i++)
        total += arr[i];
    return total;
}

template <class T>
double average(T arr[], int n) {
    return (double)sum(arr, n) / n;
}

int main() {
    int a[5] = {10, 20, 30, 40, 50};
    float b[4] = {1.5f, 2.5f, 3.5f, 4.5f};

    cout << "Integer array: sum = " << sum(a, 5)
         << ", average = " << average(a, 5) << endl;
    cout << "Float array:   sum = " << sum(b, 4)
         << ", average = " << average(b, 4) << endl;
    return 0;
}

Output

Integer array: sum = 150, average = 30
Float array:   sum = 12, average = 3

The type T is deduced from the array argument, so the same functions work for int and float arrays. The average is returned as double so that integer arrays do not lose the fractional part.