这个嵌套循环打印空心菱形的编程 怎么解读啊 在线等 求解！！

#include <iostream>;
using namespace std;
int main()
{
    int n = 9;
    int start = n / 2 + 1;
    int end = n / 2 + 1;
    bool flag = true;
    for (int i = 0; i < n; i++) {
        for (int j = 1; j <= n; j++) {
            if (j == start || j == end) {
                cout << "*";
            }
            else {
                cout << " ";
            }
        }cout << endl;
        if ((end - start + 1) == n) {
            flag = false;
        }
        if (flag) {
            start--;
            end++;
        }
        else {
            start++;
            end--;
        }
    }

     
        system("pause");
        return 0;
    
}

建议看一下这个不错的文章 C++ 打印菱形（实心和空心）_JMW1407的博客-CSDN博客 打印菱形 打印菱形1、打印实心菱形2、打印空心菱形打印菱形1、打印实心菱形#include<iostream>using namespace std;int main(){ cout << "Please enter the side length of the diamond:"; int n; cin >> n; for (int i = 0; i<n; i++) // 分为上半层打印和下半层打印，首先打 https://blog.csdn.net/JMW1407/article/details/108496082