问题及代码：
#include <iostream>#include <cstring>using namespace std;#define MAX 100class CDate // 定义日期类{private:unsigned short int year; // 年unsigned short int month; // 月unsigned short int day; // 日public:CDate(int y=0,int m=0,int d=0);//默认构造函数输入时间bool operator < (CDate d);friend istream & operator >> (istream &in,CDate &d);//输入流的提取friend ostream & operator<<(ostream &out,CDate &d);//输出流的提取friend bool CheckValid(CDate d);friend bool LeapYear(int year);void SetDate(int y,int m,int d);};CDate::CDate(int y,int m,int d):year(y),month(m),day(d) {}// 设置日期void CDate::SetDate(int y,int m,int d){year=y;month=m;day=d;}// 重载输入运算符>>istream &operator>>(istream &in,CDate &d){char ch1,ch2;cout<<"请输入日期(输入格式：YYYY-MM-DD)：";while(1){cin>>d.year>>ch1>>d.month>>ch2>>d.day;if (ch1=='-' && ch2=='-')if (CheckValid(d)) break;cerr<<"时间格式或取值不正确! 请重新输入\n";}return cin;}// 重载输出运算符<<ostream &operator<<(ostream &out,CDate &d){out<<d.year<<"年"<<d.month<<"月"<<d.day<<"日";return out;}// 判断日期d1<d2bool CDate::operator < (CDate d){if (year<d.year) return true;if (year>d.year) return false;if (month<d.month) return true;if (month>d.month) return false;if (day<d.day) return true;return false;}// 检查是否为闰年bool LeapYear(int year){if ((year%4==0 && year%100) || year%400==0)return true;return false;}// 检查日期合法性bool CheckValid(CDate d){int n;if (d.month<1 || d.month>12) return false;if (d.day<1) return false;n=31;switch(d.month){case 2:if (LeapYear(d.year))n=29;elsen=28;break;case 4:case 6:case 9:case 11:n=30;break;}if (d.day>n) return false;return true;}class CStudent{private:char *name;// 姓名bool sex;// 性别CDate date;// 出生日期，类对象作数据成员public:static int num;// 学生人数CStudent();void InputData();friend void Sort();// 排序friend void FindName(); // 按姓名查询friend void Statistic(); // 按性别统计friend void Display(); // 显示全部信息} stu[MAX];int CStudent::num=0;CStudent::CStudent() {}// 输入信息void CStudent::InputData(){int p;char s[41];cout<<"请输入学生信息（NO."<<num<<"）：\n";cout<<"姓名：";cin>>s;name=new char[strlen(s)+1];strcpy(name,s);cout<<"性别(1-男，0-女)：";cin>>p;if (p) sex=true;else sex=false;cin>>date;cout<<endl;}// 排序void Sort(){int i,j,p,num;char *tn;bool ts;CDate td;num=CStudent::num;for(i=1; i<num; i++){p=i;for(j=i+1; j<=num; j++)if (stu[j].date<stu[p].date) p=j;//找到当前未排序元素中年龄最小的对象的下标if (p==i) continue;//下面交换stu[i]和stu[p]tn=stu[i].name;stu[i].name=stu[p].name;stu[p].name=tn;ts=stu[i].sex;stu[i].sex=stu[p].sex;stu[p].sex=ts;td=stu[i].date;stu[i].date=stu[p].date;stu[p].date=td;}}// 按姓名查询void FindName(){char name[41];int i,num;cout<<"请输入姓名：";cin>>name;num=CStudent::num;for(i=1; i<=num; i++)if (strcmp(stu[i].name,name)==0) break;if (i>num){cout<<"查无此人!"<<endl<<endl;return;}//如果查到了，显示学生信息cout<<"姓名："<<stu[i].name<<endl;cout<<"性别：";if (stu[i].sex)cout<<"男"<<endl;elsecout<<"女"<<endl;cout<<"生日："<<stu[i].date<<endl;cout<<endl;}// 按性别统计void Statistic(){int i,num,s1,s0;num=CStudent::num;s1=0;s0=0;for(i=1; i<=num; i++)if (stu[i].sex==1)s1++;elses0++;cout<<"男生人数："<<s1<<endl;cout<<"女生人数："<<s0<<endl;cout<<endl;}// 显示全部信息void Display(){int i,num;num=CStudent::num;for(i=1; i<=num; i++){cout<<stu[i].name<<"\t";if (stu[i].sex)cout<<"男";elsecout<<"女";cout<<"\t"<<stu[i].date<<endl;}cout<<endl;}int main(){char *menu[]= { "","输入信息","排序","按姓名查询","按性别统计","显示全部信息","退出" };int i,p;bool end;end=false;while(!end){for(i=1; i<7; i++)cout<<i<<" "<<menu[i]<<endl;cin>>p;switch(p){case 1:// 输入信息CStudent::num++;stu[CStudent::num].InputData();break;case 2:// 排序Sort();break;case 3:// 按姓名查询FindName();break;case 4:// 按性别统计人数Statistic();break;case 5:// 显示全部信息Display();break;case 6:// 退出end=true;break;}}return 0;}
运行结果：
最快乐的时候，就是去旅行。
