三、
我修改的程式如下：
#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;
}
四、
方法一（一般法）：
#include<iostream>
using namespace std;
class Student{
public:
Student(int s, int g):sno(s), grade(g){}
// void output const();
// private:
int sno;
float grade;
};
//void Student::output const()
//{
// cout << "No." << sno << "'s grade is :" << grade << endl;
//}
void output(const Student *p)
{
cout << "No." << p->sno << "'s grade is :" << p->grade << endl;
}
int main()
{
Student s[5] = {
Student(1, 85),
Student(2, 90),
Student(3, 95),
Student(4, 99),
Student(5, 100)
};
const Student * p;
p = &s[0];
output(p);
p += 2;
output(p);
p += 2;
output(p);
// p = &s[4];
// output(p);
return 0;
}
方法二（使用了const保證類的成員資料的安全性）：
#include<iostream>
using namespace std;
class Student{
public:
Student(int s, int g):sno(s), grade(g){}
void output()const;
private:
int sno;
float grade;
};
void Student::output()const
{
cout << "No." << sno << "'s grade is :" << grade << endl;
}
int main()
{
Student s[5] = {
Student(1, 85),
Student(2, 90),
Student(3, 95),
Student(4, 99),
Student(5, 100)
};
const Student * p;
p = &s[0];
p->output();
p += 2;
p->output();
p += 2;
p->output();
return 0;
}
運作結果如下：
五、
#include<iostream>
using namespace std;
class Student{
public:
Student(int s, int g):sno(s), grade(g){}
int getsno();
float getgrade();
void getData();
private:
int sno;
float grade;
};
void Student::getData()
{
cout << "No." << sno << '\t';
cout << "grade:" << endl;
}
int Student::getsno()
{
return sno;
}
float Student::getgrade()
{
return grade;
}
int max(Student *p)
{
float max = p->getgrade();
int num = (*p).getsno();
for(; p->getgrade() != '\0'; p++)
{
if(max < p->getgrade())
{
max = p->getgrade();
num = p->getsno();
}
}
return num;
}
int main()
{
Student *p;
Student s[5] = {
Student(1, 89),
Student(2, 90),
Student(3, 96),
Student(4, 92),
Student(5, 10)
};
p = &s[0];
// cout << s[0].getgrade();
// cout << p->getgrade();
int cnt = max(p);
cout << "Winner : No." << cnt << "'s grade is :" << s[cnt - 1].getgrade() << endl;
return 0;
}
運作結果如下:
六、
#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;
}
運作結果如下：
七、
（1）常對象
（2）我修改後的程式如下：
#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;
}
運作結果美麗：
（3）運作結果如下：
（4）我修改的C++代碼如下：
#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();
const Student *p = &stud; //Student類常對象指針
(*p).change(101, 80.5);
p->display();
return 0;
}
運作結果與上題一緻
（5）
#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()
{
Student stud(101, 78.5);
stud.display();
Student * const p = &stud; //Student類常變量指針
(*p).change(101, 80.5);
p->display();
return 0;
}
運作結果與上題一緻
八、
詳細C++代碼如下：
#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;
};
void fun(Student &s, int n, float score)
{
s.display();
s.change(n, score);
s.display();
}
int main()
{
Student stud(101, 78.5);
fun(stud, 101, 80.5);
return 0;
}
九、
不知道是我沒了解正确題目還是題目有問題，那句“對于一次購10以上的客戶,還可以享受9.8折優惠”，然後再看所給的銷售情況，銷售情況裡隻有各個銷貨員總的銷貨件數，并沒有涉及到客戶是否是購了10件以上的，是以這題我就放飛自我按我自己了解的寫了（但不得不說，譚浩強的C系列的書真的好多問題，這裡不推薦初學者以這個為教材，我推薦C++ Primer）
詳細C++代碼如下：
#include<iostream>
using namespace std;
class Sell{
public:
static float aver();
static void display();
void total();
Sell(int n, int q, float p): num(n), quantity(q), price(p){}
private:
static float discount; //折扣
static float sum; //總銷售款sum
static int n; //銷售總件數n
int num;
int quantity;
float price;
};
float Sell::discount = 1.0;
float Sell::sum = 0;
int Sell::n = 0;
float Sell::aver()
{
return sum / n;
}
void Sell::display()
{
cout << "總銷售款：" << sum << endl;
cout << "每件商品的平均售價：" << aver() << endl;
}
void Sell::total()
{
if(quantity > 10)
discount = 0.98;
else
discount = 1.0;
sum += price * discount * quantity;
n += quantity;
}
int main()
{
Sell s[3] = {
Sell(101, 5, 23.5),
Sell(102, 12, 24.56),
Sell(103, 100, 21.5)
};
s[0].total();
s[1].total();
s[2].total();
s[2].display();
return 0;
}
運作結果如下：
十、
#include<iostream>
using namespace std;
class Date;
class Time{
public:
Time(int, int, int);
friend void display(Date &, Time &);
private:
int hour;
int minute;
int sec;
};
class Date{
public:
Date(int, int, int);
friend void display(Date &, Time &);
private:
int month;
int day;
int year;
};
Time::Time(int h, int m, int s)
{
hour = h;
minute = m;
sec = s;
}
void display(Date &d, Time &t)
{
cout << d.month << "/" << d.day << "/" << d.year << endl;
cout << t.hour << ":" << t.minute << ":" << t.sec << endl;
}
Date::Date(int m, int d, int y)
{
month = m;
day = d;
year = y;
}
int main()
{
Time t1(10, 13, 56);
Date d1(12, 25, 2004);
display(d1, t1);
return 0;
}
運作結果如下：
十一、
根據題意：将Time類聲明為Date類的友元類，代碼就是例3.13（嚴重懷疑譚*強國文不好）
#include<iostream>
using namespace std;
class Date;
class Time{
public:
Time(int, int, int);
void display(Date &);
private:
int hour;
int minute;
int sec;
};
class Date{
public:
Date(int, int, int);
friend void Time::display(Date &);
private:
int month;
int day;
int year;
};
Time::Time(int h, int m, int s)
{
hour = h;
minute = m;
sec = s;
}
void Time::display(Date &d)
{
cout << d.month << "/" << d.day << "/" << d.year << endl;
cout << hour << ":" << minute << ":" << sec << endl;
}
Date::Date(int m, int d, int y)
{
month = m;
day = d;
year = y;
}
int main()
{
Time t1(10, 13, 56);
Date d1(12, 25, 2004);
t1.display(d1);
return 0;
}
如果是将Date類聲明為Time的友元類，則C++代碼如下：
#include<iostream>
using namespace std;
class Time;
class Date{
public:
Date(int, int, int);
void display(Time &);
private:
int month;
int day;
int year;
};
class Time{
public:
Time(int, int, int);
friend void Date::display(Time &);
private:
int hour;
int minute;
int sec;
};
Time::Time(int h, int m, int s)
{
hour = h;
minute = m;
sec = s;
}
void Date::display(Time &t)
{
cout << month << "/" << day << "/" << year << endl;
cout << t.hour << ":" << t.minute << ":" << t.sec << endl;
}
Date::Date(int m, int d, int y)
{
month = m;
day = d;
year = y;
}
int main()
{
Time t1(10, 13, 56);
Date d1(12, 25, 2004);
d1.display(t1);
return 0;
}
運作結果同上題
十二、
改寫後的C++代碼如下：
#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." << endl;
cout << cmp1.min() << "is the Minimun." << endl;
Compare<float> cmp2(45.78, 93.6);
cout << cmp2.max() << "is the Maximum." << endl;
cout << cmp2.min() << "is the Minimun." << endl;
Compare<char> cmp3('a', 'A');
cout << cmp3.max() << "is the Maximum." << endl;
cout << cmp3.min() << "is the Minimun." << endl;
return 0;
}