7.11

#include<iostream.h>class Date {int month;int day;int year;public:Date(){}Date(int i){day=i;month=0;year=0;}Date(int m,int n,int y){year=m;month=n;     day=y;}void print(){cout<<"year.month.day"<<"  "<<year<<"."<<month<<"."<<day<<endl;}Date operator+(Date& a){      day+=a.day;return (*this);   }};int main(){Date d1(2015,5,10),d2;cout<<"输出日期d1:"<<"  ";d1.print();d2=d1+Date(1);   cout<<"输出日期d1.天数加1后的日期:"<<"  ";   d2.print();   return 0;}