c++面向对象程序设计 谭浩强 第三章答案

2:

#include <iostream>

using namespace std;

class Date

{public:

Date(int,int,int);

Date(int,int);

Date(int);

Date();

void display();

private:

int month;

int day;

int year;

};

Date::Date(int m,int d,int y):month(m),day(d),year(y)

{ }

Date::Date(int m,int d):month(m),day(d)

{year=2005;}

Date::Date(int m):month(m)

{day=1;

year=2005;

}

Date::Date()

{month=1;

day=1;

year=2005;

}

void Date::display()

{cout<<month<<"/"<<day<<"/"<<year<<endl;}

int main()

{

Date d1(10,13,2005);

Date d2(12,30);

Date d3(10);

Date d4;

d1.display();

d2.display();

d3.display();

d4.display();

return 0;

}

3:

#include <iostream>

using namespace std;

class Date

{public:

Date(int=1,int=1,int=2005);

void display();

private:

int month;

int day;

int year;

};

Date::Date(int m,int d,int y):month(m),day(d),year(y)

{ }

void Date::display()

{cout<<month<<"/"<<day<<"/"<<year<<endl;}

int main()

{

Date d1(10,13,2005);

Date d2(12,30);

Date d3(10);

Date d4;

d1.display();

d2.display();

d3.display();

d4.display();

return 0;

}

4:

#include <iostream>

using namespace std;

class Student

{public:

Student(int n,float s):num(n),score(s){}

void display();

private:

int num;

float score;

};

void Student::display()

{cout<<num<<" "<<score<<endl;}

int main()

{Student stud[5]={

Student(101,78.5),Student(102,85.5),Student(103,98.5),

Student(104,100.0),Student(105,95.5)};

Student *p=stud;

for(int i=0;i<=2;p=p+2,i++)

p->display();

return 0;

}

5:

#include <iostream>

using namespace std;

class Student

{public:

Student(int n,float s):num(n),score(s){}

int num;

float score;

};

void main()

{Student stud[5]={

Student(101,78.5),Student(102,85.5),Student(103,98.5),

Student(104,100.0),Student(105,95.5)};

void max(Student* );

Student *p=&stud[0];

max(p);

}

void max(Student *arr)

{float max_score=arr[0].score;

int k=0;

for(int i=1;i<5;i++)

if(arr[i].score>max_score) {max_score=arr[i].score;k=i;}

cout<<arr[k].num<<" "<<max_score<<endl;

}

c++面向对象程序设计

6:

#include <iostream>

using namespace std;

class Student

{public:

Student(int n,float s):num(n),score(s){}

void change(int n,float s) {num=n;score=s;}

void display(){cout<<num<<" "<<score<<endl;}

private:

int num;

float score;

};

int main()

{Student stud(101,78.5);

stud.display();

stud.change(101,80.5);

stud.display();

return 0;

}

c++面向对象程序设计 谭浩强 答案

7: 解法一

#include <iostream>

using namespace std;

class Student

{public:

Student(int n,float s):num(n),score(s){}

void change(int n,float s) {num=n;score=s;}

void display() {cout<<num<<" "<<score<<endl;}

//可改为:void display() const {cout<<num<<" "<<score<<endl;}

private:

int num;

float score;

};

int main()

{const Student

stud(101,78.5);

stud.display();

//stud.change(101,80.5);

stud.display();

return 0;

}

c++面向对象程序设计 谭浩强 答案

解法二：

#include <iostream>

using namespace std;

class Student

{public:

Student(int n,float s):num(n),score(s){}

void change(int n,float s) const  {num=n;score=s;}

void display() const {cout<<num<<" "<<score<<endl;}

private:

mutable int num;

mutable float score;

};

int main()

{const Student stud(101,78.5);

stud.display();

stud.change(101,80.5);

stud.display();

return 0;

}

解法三：

#include <iostream>

using namespace std;

class Student

{public:

Student(int n,float s):num(n),score(s){}

void change(int n,float s) {num=n;score=s;}

void display() {cout<<num<<" "<<score<<endl;}

private:

int num;

float score;

};

c++面向对象程序设计 谭浩强 答案

int main()

{Student stud(101,78.5);

Student *p=&stud;

p->display();

p->change(101,80.5);

p->display();

return 0;

}

8：

#include <iostream>

using namespace std;

class Student

{public:

Student(int n,float s):num(n),score(s){}

void change(int n,float s) {num=n;score=s;}

void display() {cout<<num<<" "<<score<<endl;}

private:

int num;

float score;

};

int main()

{Student stud(101,78.5);

void fun(Student&);

fun(stud);

return 0;

}

void fun(Student &stu)

{stu.display();

stu.change(101,80.5);

stu.display();

}

谭浩强

9：

#include <iostream>

using namespace std;

class Product

{public:

Product(int n,int q,float p):num(n),quantity(q),price(p){};

void total();

static float average();

static void display();

private:

int num;

int quantity;

float price;

static float discount;

static float sum;

static int n;

};

void Product::total()

{float rate=1.0;

if(quantity>10) rate=0.98*rate;

sum=sum+quantity*price*rate*(1-discount);

n=n+quantity;

}

void Product::display()

{cout<<sum<<endl;

cout<<average()<<endl;

}

float Product::average()

{return(sum/n);}

float Product::discount=0.05;

float Product::sum=0;

int Product::n=0;

int main()

{

Product Prod[3]={

Product(101,5,23.5),Product(102,12,24.56),Product(103,100,21.5)

};

for(int i=0;i<3;i++)

Prod[i].total();

Product::display();

return 0;

}

c++面向对象程序设计 谭浩强

10：

#include <iostream>

using namespace std;

class Date;

class Time

{public:

Time(int,int,int);

friend void display(const Date &,const Time &);

private:

int hour;

int minute;

int sec;

};

c++面向对象程序设计

Time::Time(int h,int m,int s)

{hour=h;

minute=m;

sec=s;

}

class Date

{public:

Date(int,int,int);

friend void display(const Date &,const Time &);

private:

int month;

int day;

int year;

};

Date::Date(int m,int d,int y)

{month=m;

day=d;

year=y;

}

void display(const Date &d,const Time &t)

{

cout<<d.month<<"/"<<d.day<<"/"<<d.year<<endl;

cout<<t.hour<<":"<<t.minute<<":"<<t.sec<<endl;

}

int main()

{

Time t1(10,13,56);

Date d1(12,25,2004);

display(d1,t1);

return 0;

}

11：

#include <iostream>

using namespace std;

class Time;

class Date

{public:

Date(int,int,int);

friend Time;

private:

int month;

int day;

int year;

};

Date::Date(int m,int d,int y):month(m),day(d),year(y){ }

class Time

{public:

Time(int,int,int);

void display(const Date &);

private:

int hour;

int minute;

int sec;

};

Time::Time(int h,int m,int s):hour(h),minute(m),sec(s){ }

void Time::display(const Date &d)

{

cout<<d.month<<"/"<<d.day<<"/"<<d.year<<endl;

cout<<hour<<":"<<minute<<":"<<sec<<endl;

}

int main()

{

Time t1(10,13,56);

Date d1(12,25,2004);

t1.display(d1);

return 0;

}

12：

#include <iostream>

using namespace std;

template<class numtype>

class Compare

{public:

Compare(numtype a,numtype b);

numtype max();

numtype min();

private:

numtype x,y;

};

template <class numtype>

Compare<numtype>::Compare(numtype a,numtype b)

{x=a;y=b;}

template <class numtype>

numtype Compare<numtype>::max()

{return (x>y)?x:y;}

template <class numtype>

numtype Compare<numtype>::min()

{return (x<y)?x:y;}

int main()

{Compare<int> cmp1(3,7);

cout<<cmp1.max()<<" is the Maximum of two integer numbers."<<endl;

cout<<cmp1.min()<<" is the Minimum of two integer numbers."<<endl<<endl;

Compare<float> cmp2(45.78,93.6);

cout<<cmp2.max()<<" is the Maximum of two float numbers."<<endl;

cout<<cmp2.min()<<" is the Minimum of two float numbers."<<endl<<endl;

Compare<char> cmp3('a','A');

cout<<cmp3.max()<<" is the Maximum of two characters."<<endl;

cout<<cmp3.min()<<" is the Minimum of two characters."<<endl;

return 0;

}