example3_robust_numerics.cpp

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
#include <iostream>
#include <limits>
#include <vector>
#include <algorithm>

template<typename T>
T safe_average(const std::vector<T>& numbers) {
    if (numbers.empty()) {
        return T(0);
    }

    T sum = 0;
    size_t count = 0;

    for (const T& num : numbers) {
        // Check for overflow before adding
        if (num > 0 && sum > std::numeric_limits<T>::max() - num) {
            throw std::overflow_error("Sum would overflow");
        }
        if (num < 0 && sum < std::numeric_limits<T>::min() - num) {
            throw std::underflow_error("Sum would underflow");
        }
        sum += num;
        ++count;
    }

    return sum / count;
}

int main() {
    try {
        std::vector<int> ints = {1, 2, 3, 4, 5};
        std::cout << "Average of ints: " << safe_average(ints) << std::endl;

        std::vector<double> doubles = {1.1, 2.2, 3.3, 4.4, 5.5};
        std::cout << "Average of doubles: " << safe_average(doubles) << std::endl;

        std::vector<int> large_ints = {std::numeric_limits<int>::max(), 1};
        std::cout << "Average of large ints: " << safe_average(large_ints) << std::endl;
    } catch (const std::exception& e) {
        std::cerr << "Error: " << e.what() << std::endl;
    }

    return 0;
}