c++联合体

构建类examscore，用于存放学生姓名，年龄，成绩存储方式和 成绩4个数据，其中联合体有三种数据类型故可存放百分制，等级，过关与否三种形式的成绩，具体情况根据构造时调用的构造函数，所以又会有三种构造函数，当构造对象的成绩为int类型时，联合体取percent，枚举mode取percent作为标记（用于show函数），其他类型的成绩类似推理；

#include
#include
using namespace std;

class examscore {

public:
string name;
int age;
enum {Percent,Dengji,Ifpass} mode;
union{
	     int percent;
	     char dengji;
	     bool  ifpass;
     };
void show();
examscore(string name, int age, int percent);
examscore(string name, int age, char dengji);
examscore(string name, int age, bool ifpass); 
};

//构造函数及show函数

examscore::examscore(string name, int age, int percent) : name(name), age(age) ,mode(Percent),percent(percent){}
examscore::examscore(string name, int age, char dengji) : name(name), age(age), mode(Dengji), dengji(dengji) {}
examscore::examscore(string name, int age, bool ifpass) : name(name), age(age), mode(Ifpass), ifpass(ifpass) {}
void examscore:: show()
{
cout << name << ":";
  switch (mode) 
  {
  case Percent:cout << percent; break;
  case Dengji:cout << dengji; break;
  case Ifpass:cout << ifpass; break;
  }
cout<<endl;
}

//主函数

int main()
{
examscore a("a", 20, 88);
a.show();
examscore b("b", 20, 'A');
b.show();
examscore c("c", 20, false);
c.show();
return 1;
}