没人发？那我搞个

#include <bits/stdc++.h>
using namespace std;
int main()
{
    int a;
    cin >> a;
    for (int i = 1;i < a;i++)
    {
        cout << " ";
    }
    for (int i = 1;i <= a;i++)
    {
        cout << "*";
    }
    cout << endl;
    for (int i = 1;i < a;i++)
    {
        for (int j = 1;j <= a - i - 1;j++)
        {
            cout << " ";
        }
        cout << "*";
        for (int j = 1;j <= a + (i - 1) * 2;j++)
        {
            cout << " ";
        }
        cout << "*";
        cout << endl;
    }
    for (int i = a - 2;i > 0;i--)
    {
        for (int j = 1;j <= a - i - 1;j++)
        {
            cout << " ";
        }
        cout << "*";
        for (int j = 1;j <= a + (i - 1) * 2;j++)
        {
            cout << " ";
        }
        cout << "*";
        cout << endl;
    }
    for (int i = 1;i < a;i++)
    {
        cout << " ";
    }
    for (int i = 1;i <= a;i++)
    {
        cout << "*";
    }
    cout << endl;
}//已AC，请放心食用