[c++]杨辉三角

#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
	int n;
	cout << "please enter the line you want(MAX=30):" << endl;
	cin >> n;
	int a[30][30];
	for (int i = 0; i < n; i++)
	{
		a[i][0] = 1;
		a[i][i] = 1;
	}
	for (int i = 1; i < n; i++)
	{
		for (int j = 1; j < i; j++)
		{
			a[i][j] = a[i - 1][j - 1] + a[i - 1][j];
		}
	}
	for (int i = 0; i < n; i++)
	{
		for (int k = 0; k < n-i; k++)
			cout <<"  ";
		for (int j = 0; j <= i; j++)
		{
			cout << a[i][j] << "  ";
		}
		cout << endl;
	}
	return 0;
}