第三章作业

3.22

#include<iostream>#include<math.h>using namespace std;class Circle{public:void area(int x,double y);void show();private:int radius;double Area;};void Circle::area(int x,double y){radius=x;Area=y;}void Circle::show(){cout<<"半径为R的圆的面积为："<<Area<<endl;}int main(){Circle circle1;int a;double b;cout<<"请输入圆的半径R：";cin>>a;b=3.14*a*a;circle1.area(a,b);circle1.show();return 0;}

3.23

#include<iostream>using namespace std;struct cylinder{public:void set(double x,double y,double z){r=x;h=y;v=z;};void show();private:double r;double h;double v;};void cylinder::show(){cout<<"该圆柱体的底面半径为："<<r<<endl<<"高为："<<h<<endl<<"体积是："<<v<<endl;}int main(){cylinder vo1;double a,b,c;a=3.0;b=4.0;c=3.14*a*a*b;vo1.set(a,b,c);vo1.show();return 0;}

3.24

<p><pre name="code" class="cpp">#include<iostream>using namespace std;class Date{public:Date(int a,int b,int c);Date();void printDate();void GetYear();void GetMonth();void GetDay();void SetDate(int Y,int m,int d){year=Y;month=m;day=d;}private:int year;int month;int day;};Date::Date(int a,int b,int c):year(a),month(b),day(c){}Date::Date(){}void Date::printDate(){cout<<year<<"."<<month<<"."<<day<<endl;}void Date::GetYear(){cout<<"输入一个年份：";cin>>year;}void Date::GetMonth(){cout<<"输入一个月份：";cin>>month;}void Date::GetDay(){cout<<"输入一个日子：";cin>>day;}int main(){Date d1(2010,6,8);d1.printDate();Date d2;d2.GetYear();d2.GetMonth();d2.GetDay();d2.printDate();Date d3(d1);d3.printDate();return 0;}