我如何为此添加错误消息?例如:您不小心按下了成绩中的一个字母而不是数字,然后会显示一条错误消息 #包括 使用命名空间标准;
int main()
{
double assignment1, assignment2, seatwork1, seatwork2, quiz1, quiz2, majorexam, grade, major, assignment, seatwork, quiz;
string name;
cout<<"Enter Student name: ";
cin>>name;
cout<<"Enter grade for assignment 1: ";
cin>>assignment1;
cout<<"Enter grade for assignment 2: ";
cin>>assignment2;
cout<<"\nEnter grade for seatwork 1: ";
cin>>seatwork1;
cout<<"Enter grade for seatwork 2: ";
cin>>seatwork2;
cout<<"\nEnter grade for quiz 1: ";
cin>>quiz1;
cout<<"Enter grade for quiz 2: ";
cin>>quiz2;
cout<<"\nEnter grade for major exam: ";
cin>>majorexam;
float aveAssignment=(assignment1+assignment2)/2;
assignment = (aveAssignment)*.1;
float aveSeatwork=(seatwork1+seatwork2)/2;
seatwork = (aveSeatwork)*.2;
float aveQuiz=(quiz1+quiz2)/2;
quiz = (aveQuiz)*.3;
major = majorexam*.4;
grade = (assignment+seatwork+quiz+major);
cout<<"Final Grade is: "<<grade;
return 0;
}