第1-7章C面向对象程序设计作业参考答案.pdf

1 第第1章章 1.2 【解答】 重点：标准输入输出库函数标准输入输出流对象 #include int main() char name20; coutname; cout using namespace std; /Overload max( ) three ways 重载函数名 max 三次 int max(int a,int b); long max(long a,long b); double max(double a,double b); int main() int a1=3,b1=10; long a2=123456,b2=567893; double a3=2*106,b3=-12.34; coutb?c=a:c=b; return(c); long max(long a,long b) long c; ab?c=a:c=b; return(c); double max(double a,double b) double c; ab?c=a:c=b; return(c); 4 1.9 要点：申请动态数组 【解答】 / A simple example of new and delete. #include #include using namespace std; const int N=10; int main( ) char *p,q; int i=0; p=new charN; /allocate memory for a array 为数组分配动态内存空间 if(p=NULL) coutq; while(q!=#) pi+=q; cinq; cout void f(int a ,int n, int for(int i=1;iai) min=ai; void main( ) int a10=2,5,3,9,0,8,1,7,6,4; int max,min; f(a,10,max,min); cout #include class my_string private: char *contents; int length; public: my_string(char *s); void show(); int getlength(); void add(char *s); ; my_string:my_string(char *s) contents=new charstrlen(s)+1; strcpy(contents,s); length=strlen(s); 8 void my_string:show() cout class Rectangle private: int length; int width; public: Rectangle(int l,int w); 9 int area(); ; Rectangle:Rectangle(int l,int w) length=l; width=w; int Rectangle:area() return (length*width); void main() Rectangle Rect(10,15); cout）运算符。 【解答】 #include #include class Student 11 private: int number; char name15; float score; public: Student(int number1,char *name1,float score1); /构造函数的声明 void modify(float score1) score=score1; void print( ); ; /构造函数的定义 Student:Student (int number1,char *name1,float score1) number=number1; strcpy(name,name1); score=score1; void Student:print( ) coutprint(); 12 return 0; 4.3 阅读下列程序，指出其中的错误。并分析出错的原因。 #include using namespace std; class myclass int a, b; public: void set(int i, int j) a = i; b = j; void show() cout class Circle public: Circle(float r) radius=r; +count; 14 Circle() -count; static int num() return count; private: float radius; static int count; ; int Circle:count=0; void main() Circle c1(10),c2(20); cout using namespace std; class Square int side; public: Square(int x) side = x; coutdisplay(); delete ps; /自动调用析构函数，然后释放堆内存 return 0; 5.3 假设有以下的类定义， class Square int side; public: Square(int x=10) side = x; cout using namespace std; class X public: X() p = new int2; cout #include #include using namespace std; class strtype char *p; public: strtype(char *s); strtype() delete p; char *get() return p; ; strtype:strtype(char *s) int l; l = strlen(s)+1; p = new char l; if(!p) cout #include #include using namespace std; class strtype char *p; public: strtype(char *s); strtype(const strtype strtype() delete p; char *get() return p; ; strtype:strtype(char *s) int l; l = strlen(s)+1; p = new char l; if(!p) cout class A protected: 22 int m,n; public: void set(int a, int b) m=a; n=b; void show( ) cout 23 class planet protected: double distance; / miles from the sun int revolve; / in days public: planet(double d,int r) distance=d; revolve=r; ; class earth: public planet double circumference; / circumference of orbit public: earth(double d,int r):planet(d,r) circumference=2*r*3.1416; void show() cout运算符。 ? 在重载增值和减值运算符时， 用 friend operator 函数需要使用引用参 数。 C+的大部分运算符即可以说明为成员函数运算符，也可以说明成友元函数 运算符。究竟选择哪一种运算符函数好一些，没有定论，这主要取决于实际 情况和程序员的习惯。 第第7章章 7.3 完成下列的 String 类，并在主函数 main( )中测试它。 class String public: String(const char *str = NULL); / constructor String(const String / copy constructor String(void); / destructor String String / 重载=运算符 int operator=(String / 重载=运算符 int operator=(char *str); private: char *m_data; / used for storing the string int length; ; 【解答】 25 #include #include class String public: String(char *str); / constructor String(const String / copy constructor String() / destructor String String / 重载=运算符 int operator=(String / 重载=运算符 int operator=(char *str); private: char *m_data; / used for storing the string int length; ; String:String(char *str) length=strlen(str); m_data=new charlength+1; strcpy(m_data,str); String:String(const String strcpy(m_data,other.m_data); length=other.length; String String int String:operator=(String else return 0; int String:operator=(char *str) if(strcmp(m_data,str)=0) return 1; else return 0; void main() String s1(“Hello“),s2(“hello“); String s3(s1); if(s1=s2) cout class three_d int x,y,z; public: three_d(int i, int j ,int k) x = i ,y =j ,z = k; three_d( ) x = 0 ,y =0 ,z = 0; void get(int three_d three_d operator + (three_d); three_d 30 three_d void print() cout“x:“x“y:“y“z“zendl; ; three_d y=t.y; z=t.z; return *this; three_d three_d:opera