第8章 习题解答8.1判断题对的有4,6,7,9,11,13,15,16,18,20,21,23,24,25.268.2单选题CDADC ACCBC8.3填空题1. public private protected2. 私有 公有3. 默认 默认4. 类 :5. 类体 非 所有6. friend A A8.4程序结果1. Default constructor called.Constructor called.a1=0,a2=0a1=5,a2=8Destructor called.Destructor called.2. 111213131312113. 2005/10/12005/12/94. c1=12,c2=185. 11,2,3,4,5101,2,3,4,5,6,7,8,9,108.5编程题 1. #include class Rectangle public: Rectangle(int i,int j) width=i;length=j; double Perimenter() return 2*(width+length); double Aear() return width*length; void ChangeSize(int x,int y) width=x;length=y; void Print() coutwidth=width,length=lengthendl; private: double width,length;void main() Rectangle r1(10,12),r2(8,15); coutRectangle r1:n; r1.Print(); coutPerimenter: r1.Perimenter()endl; coutAear: r1.Aear()endlendl; coutRectangle r2:n; r2.Print(); coutPerimenter: r2.Perimenter()endl; coutAear: r2.Aear()endlendl; r1.ChangeSize(20,18); coutChange Rectangle r1:n; r1.Print(); coutPerimenter: r1.Perimenter()endl; coutAear: r1.Aear()endlendl; 2. #include class Calculator public: Calculator(double i,double j) x=i;y=j; double Add() return x+y; double Sub() return x-y; double Mul() return x*y; double Div() return x/y; void Print() coutx=x,y=yendl; private: double x,y;void main() double d1,d2; coutd1d2; Calculator c(d1,d2); c.Print(); coutc.Add()endl; coutc.Sub()endl; coutc.Mul()endl; coutc.Div()endl; 3. #include class Student public: Student(char n,int i) name=n; score=i; totalScore+=score; count+; static int TotalScore() return totalScore; static double Average() return (double)totalScore/count; void Print() coutnmae=name,score=scoreendl; private: char *name; int score; static int totalScore,count;int Student:totalScore=0;int Student:count=0;void main() Student s1(Ma,98),s2(Lu,90),s3(Hu,88),s4(li,85),s5(Gao,85); s2.Print(); s5.Print(); coutTotalScore=Student:TotalScore()endl; coutAverage=Student:Average()endl; 8.6 回答问题1. 答：不一定，用户不定义任何构造函数时系统会自动创建黙认的构造函数。可使用系统会自动创建的黙认构造函数给对象初始化。2. 答：有一个参数。没有。3. 答：可以。4. 答：不可以。可以。5. 答：可以。不全相同。4