定义一个int类a，输入a，怎样使在键盘输入非数字字符时提示错误并重新输入？

Question

void CRecord::InputOutputRecord()//增加支出数据
{
int year,month,day;
double output;
char purpose[20];
cout<<"\n请输入日期：(例如:2012 2 29)";
cin>>year>>month>>day;

while(!IsDateRight(year,month,day))
{
    cout<<"\n日期不正确!请重新输入：(例如:2012 2 29)";
    cin>>year>>month>>day;
}
cout<<"\n请输入支出金额：";
cin>>output;
cout<<"\n请输入支出用途：";
cin>>purpose;

CFinance*pfinance=new CFinance;
pfinance->SetFinance(year,month,day,0,output,purpose);
CNode*pnode=new CNode;
pnode->InputData(pfinance);
list.Insert(pnode);
cout<<"\n添加成功!\n"<<endl;
list.CalBalance();

}
bool IsDateRight(int year,int month,int day)//判断日期是否正确的函数
{
if(year3000)return false;
if(month12)return false;
int DaysInMonth;
switch(month)
{
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12:DaysInMonth=31;
break;
case 4:
case 6:
case 9:
case 11:DaysInMonth=30;
break;
case 2:
{
if((year%4==0&&year%100!=0)||year%400==0)DaysInMonth=29;
else DaysInMonth=28;
break;
}
}
if(dayDaysInMonth)return false;
if(day>0&&day<=DaysInMonth)return true;
return false;
}
输入日期时如果输字母程序就崩了，，，

Answer 1

可以用
do
{
cin >> n;
}
while (n合法性判断);