C++第七次上机实验

#include <iostream.h>void main(){int i,j,n,a[100][100];charch;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]<<"   ";elseif(a[i][j]<100)cout<<a[i][j]<<"  ";elsecout<<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');}