1+2+3+...+n（递归以及循环实现）

递归：1.031s

#include<iostream>
using namespace std;

int AddFrom1ToN_Recursive(int n)
{
    return n <= 0 ? 0 : n + AddFrom1ToN_Recursive(n - 1);
}

int main()
{
    int result = AddFrom1ToN_Recursive(100);
    cout << result << endl;

    return 0;
}

循环：0.931s

#include<iostream>
using namespace std;

int AddFrom1ToN_Iterative(int n)
{
    int result = 0;
    for (int i = 1; i <= n; i++)
    {
        result += i;
    }

    return result;
}

int main()
{
    int result = AddFrom1ToN_Iterative(100);
    cout << result << endl;

    return 0;
}