C++第七次上机实验

#include <iostream.h>
void main()
{
	int i,j,n,a[100][100];
	char	ch;
	do
	{
		cout<<"\n\tPlease enter n(>2)=:";
		cin>>n;
		while(n<=2)
		{
			cout<<"\n\t\t\a\aInput Error!Please enter n(n>2)=";
			cin>>n;
		}
		for(i=0;i<n;i++)
		{
			a[i][0]=1;
			a[i][i]=1;
			for(j=1;j<i;j++)
				a[i][j]=a[i-1][j-1]+a[i-1][j];
		}
		for(i=0;i<n;i++)
		{
			cout<<"\n";
			for(j=0;j<2*(n-1)-2*i;j++)
				cout<<" ";
			for(j=0;j<i+1;j++)
			{
				if(a[i][j]<10)
					cout<<a[i][j]<<"   ";
				else	if(a[i][j]<100)
					cout<<a[i][j]<<"  ";
				else
					cout<<a[i][j]<<" ";
			}
		}
		cout<<"\n\t\t\a\a是否继续做下一题？ (y/n)";
		cin>>ch;
		while(!(ch=='n'||ch=='N'||ch=='y'||ch=='Y'))
		{
			cout<<"\n\t\t\a\aInput Error!Continue!?? (y/n)";
			cin>>ch;
		}
		cin.ignore();
	}while(ch=='y'||ch=='Y');
}