类与对象3

#include<string>
#include<iostream>
using namespace std;
class ExamInfo{
public:
ExamInfo(string name,char grade)
:name(name),mode(GRADE),grade(grade){}
ExamInfo(string name,bool pass)
:name(name),mode(PASS),pass(pass){}
ExamInfo(string name,int percent)
:name(name),mode(PERCENTAGE),percent(percent){}
void show();
private:
string name;
enum {
GRADE,
PASS,
PERCNETANGE
}mode;
union {
char grade;
bool pass;
int percent;
};
};
void ExamInfo::show(){
cout<<name<<":";
switch (mode){
case GRADE:cout<<grade;
break;
case PASS:
cout<<(pass ? "PASS":"FAIL");
break;
case PERCENTAGE:
cout<<percent;
break;
}
cout<<endl;
}
int main()
{
ExamInfo course1("English",'B');
ExamInfo course2("Calculus",true);
ExamInfo course3("C++Programming",85);
course1.show();
course2.show();
course3.show();
return 0;
}