就直接模拟输出注意对齐和空格

#include<bits/stdc++.h>
typedef long long LL;
using namespace std;

int main ()
{
	int n,n1,n2;
	char c = '*';
	cin >> n;
	n1 = (n + 1) / 2;
	n2 = n / 2;
	for(int i = 1;i <= n1;++ i)//上层 
	{
		for(int j = 1;j < i;++ j)
		{
			cout << " ";//打印空格 
		}
		for(int j = 1;j <= (n1 - i) * 2 + 1;++ j)
		{
			cout << c;
		}
		cout << "\n"; 
	}
    for(int i = 1;i <= n2;++ i)//下层 
    {
        for (int j = 1; j < n2 - i + 1;++ j)
            cout << " ";
        for (int j = 1; j <= 2 * i + 1; j++)
            cout << c;
        cout << "\n";
    }
	
	return 0;
}