过分简单……

#include <iostream>
using namespace std;
int x;

int main()
{
    cin >> x;
    for (int i = 1; i <= x; i++)
    {
        for (int j = 1; j <= x - i; j++)
        {
            cout << " ";
        }
        for (int j = 1; j <= i * 2 - 1; j++)
        {
            cout << "*";
        }
        cout << endl;
    }
    return 0;
}

AC过的~

找规律输出即可

参考代码（已AC）：

#include <bits/stdc++.h>
using namespace std;
int n;
int main()
{
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=n-i;j++)//输出空格
            cout<<" ";
        for(int j=1;j<=i*2-1;j++)//输出*
            cout<<"*";
        cout<<endl;//换行
    }
    return 0;
}

要是实在找不到规律的话，可以添加一个变量

#include <bits/stdc++.h>
using namespace std;
int n,x=1;//x初始化为1
int main()
{
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=n-i;j++)//输出空格
            cout<<" ";
        for(int j=1;j<=x;j++)//输出*
            cout<<"*";
        x+=2;//每一行输出结束，x增加2
        cout<<endl;//换行
    }
    return 0;
}

#include <iostream> using namespace std; int main() { int n; cin >> n; for (int i = 1; i <= n; i++) { for (int j = 1; j <= n - i; j++) { cout << " "; } for (int j = 1; j <= 2 * i - 1; j++) { cout << "*"; } cout << endl; } return 0; }

#include <iostream>
using namespace std;
int main()
{
    int n; 
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= n - i; j++)
        {
            cout << " ";
        }
        for (int j = 1; j <= i * 2 - 1; j++)
        {
            cout << "*";
        }
        cout << endl;
    }
    return 0;
}

#include <iostream> using namespace std; int n ; int main() { cin >> n ; for ( int i = 1 ; i <= n ; i++ ) { for ( int j = 1 ; j <= n - i ; j++ ) cout << " " ; for ( int j = 1 ; j <= ( ( i - 1 ) * 2 ) + 1 ; j++ ) cout << "*" ;//找出规律就可以了~ cout << endl ; } return 0 ; }