题解 | #求 1 - n 之间偶数的和#

#include <iostream>
using namespace std;

int main() {
    
    int n;
    cin >> n;
    int sum = 0;
    
    // write your code here......
    for (int i = 0; i <= n; i++)
    {
        if (i % 2 == 0)  //说明是偶数
        {
            sum = sum + i;
        }
    }

    cout << sum << endl;
    
    return 0;
}