推导出的返回类型

#include <iostream>
#include <vector>

auto sum(const std::vector<int>& nums) {
    int total = 0;
    for (const auto& num : nums) {
        total += num;
    }
    return total; // 返回类型推导为 int
}

int main() {
    std::vector<int> numbers = {1, 2, 3, 4, 5};
    std::cout << "Sum: " << sum(numbers) << std::endl;
    return 0;
}

import java.util.List;

public class Main {
    public static void main(String[] args) {
        List<Integer> numbers = List.of(1, 2, 3, 4, 5);
        System.out.println("Sum: " + sum(numbers));
    }

    public static var sum(List<Integer> nums) {
        int total = 0;
        for (var num : nums) {
            total += num;
        }
        return total; // 返回类型推导为 int
    }
}

fun main() {
    val numbers = listOf(1, 2, 3, 4, 5)
    println("Sum: ${sum(numbers)}")
}

fun sum(nums: List<Int>): Int {
    var total = 0
    for (num in nums) {
        total += num
    }
    return total // 返回类型推导为 Int
}

auto complexFunction(int a, int b) {
    if (a > b) {
        return a + b; // 返回类型推导为 int
    } else {
        return static_cast<double>(a) / b; // 返回类型推导为 double
    }
}

double complexFunction(int a, int b) {
    if (a > b) {
        return static_cast<double>(a + b); // 显式指定返回类型为 double
    } else {
        return static_cast<double>(a) / b; // 显式指定返回类型为 double
    }
}