#include<iostream>
int main()
{
	using namespace std;
	const int N = 4;
	//前四行
	for (int i = 1; i <= N; i++)
	{
		for (int j = 1; j <= 30; j++) //在图案左侧空30列
			cout << " ";
		for (int j = 1; j <= 8 - 2 * i;j++)
			cout << " ";
		for (int j = 1; j <= 2 * i - 1; j++)
			cout << "*";
		    cout << endl;

	}
	//后三行
	for (int i = 1; i < N; i++)
	{
		for (int j = 1; j <= 30; j++)//在图案左侧空30列
			cout << " ";
		for (int j = 1; j <= 7 - 2 * i; j++)
			cout << "*";
			cout << endl;

	}
}

结果如下:

如果要想输出如下图案:

#include<iostream>
int main()
{
	using namespace std;
	const int N = 4;
	//前四行
	for (int i = 1; i <= N; i++)
	{
		for (int j = 1; j <= 30; j++) //输出
			cout << " ";
		for (int j = 1; j <= 8 - 2 * i;j++)
			cout << " ";
		for (int j = 1; j <= 2 * i - 1; j++)
			cout << "*";
		    cout << endl;

	}
	//后三行
	for (int i = 1; i <= N; i++)
	{
		for (int j = 1; j <= 22; j++)
			cout << " ";
		for (int j = 1; j <= 9 - 2 * i; j++)
			cout << "*";
			cout << endl;

	}
}

输出菱形

#include <iostream>
#include <math.h>
#include <vector>
#include <algorithm>
using namespace std;

int main()
{
	//外层循环控制行、换行
	//内层循环控制列、列的图形
	//中分的三角菱形
	//定义半菱形高度，即定义了菱形的大小
	int n;
	cout << "请输入半菱形高度" << endl;
	cin >> n;
	//上半部分居中正三角n行
	for (int i = 0; i < n; i++)
	{
		for (int j = 0; j < n - i - 1; j++)
		{
			cout << " ";
		}
		for (int j = 0; j <= 2 * i; j++)
		{
			//每行第一个和最后一个外打印星号，其余打印空格，做成空心效果，下半部分相同
			if (j == 0 || j == 2 * i)
				cout << "*";
			else
				cout << " ";
		}
		cout << endl;
	}

	//下半部分居中倒三角n-1行
	for (int i = 0; i < n - 1; i++)
	{
		for (int j = 0; j <= i; j++)
		{
			cout << " ";
		}
		for (int j = 0; j <= 2 * (n - i - 2); j++)
		{
			if (j == 0 || j == 2 * (n - i - 2))
				cout << "*";
			else
				cout << " ";
		}
		cout << endl;
	}
	return 0;
}