c++程序設(shè)計(jì)課后練習(xí)答案(共51頁(yè))

1、精選優(yōu)質(zhì)文檔-傾情為你奉上第一章 一、選擇題 1.B; (typedef ,typeid ,typename，都為保留字); 2.C; (標(biāo)識(shí)符，應(yīng)該以字母或，下劃線開(kāi)頭); 3.C; (標(biāo)識(shí)符中有的特殊符號(hào)，只能有下劃線); 二、填空題 1. cin，cout 2. new，delete3. int a(55); 三、改錯(cuò)題 1.沒(méi)有定義變量num; 2.const int *p=&x;是聲明指向常量的指針， *p不能當(dāng)作“左值”，*p=65錯(cuò)誤。 3.p為常量指針，不能吧p作為“左值”，p=&y，錯(cuò)誤。 四、編程題 1. 分別用字符和ASCII碼形式輸出整數(shù)值65和66.

2、#include < iostream >using namespace std;void main()char a='A',b='B'int ascii_1=53,ascii_2=54;/ASCII碼中的，5和6cout<<"字符輸出："<<(int)a<<"，"<<(int)b<< endl;cout<<"ASCII碼輸出："<<(char)ascii_2<<(char)ascii_1<

3、<"，"cout<<(char)ascii_1<<(char)ascii_1<< endl;2.編寫(xiě)一個(gè)int型變量分配100個(gè)整形空間的程序。#include < iostream >using namespace std;void main()int *p;p = new int100;for(int i = 0;i < 100;i+)*(p+i)=i;for(i = 0;i < 100;i+)cout<<*(p+i)<<"，"delete p;3.編寫(xiě)完整的程

4、序，它讀入15個(gè)float值，用指針把它們存放在一個(gè)存儲(chǔ)快里，然后輸出這些值和以及最小值。 #include < iostream >#include < algorithm > /用于數(shù)組排列的頭文件using namespace std;void main()float *p;p = new float15;cout<<"輸入15個(gè)float類(lèi)型的值：" << endl;for(int i = 0;i < 15 ; i+)cin>>*(p+i);for(i = 0;i < 15;i+)cout<

5、;<*(p+i)<<"，"sort(p,p+15);cout<<"n最小的是："<<*(p)<< endl;delete p;4.聲明如下數(shù)組：int a = 1 ,2 ,3, 4, 5, 6, 7, 8；先查找4的位置，講數(shù)組a復(fù)制給數(shù)組b，然后將數(shù)組a的內(nèi)容反轉(zhuǎn)，再查找4的位置，最后分別輸出數(shù)組a和b的內(nèi)容。#include < iostream>#include < algorithm>#include < functional>using namespace

6、 std;void main()int a=1,2,3,4,5,6,7,8,b8;cout<<"數(shù)組a中4的位置是："<< find(a,a+8,4)<< endl;/查找4的位置copy(a,a+8,b);/將數(shù)組a復(fù)制給數(shù)組breverse_copy(b,b+8,a);/把數(shù)組b，逆向復(fù)制給a，完成a的逆轉(zhuǎn)cout<<"數(shù)組a反轉(zhuǎn)后，4的位置是："<< find(a,a+8,4)<< endl;/在查找4的位置cout<<"數(shù)字a的內(nèi)容："<

7、< endl;for(int i=0;i<8;i+)cout<< ai<<" ,"cout<<"n數(shù)組b中的內(nèi)容："<< endl;for(i=0;i<8;i+)cout<< bi<<" ,"第二章 一、單項(xiàng)選擇1.D； 2.D； 三、編程題 1.使用多種方法編寫(xiě)將兩個(gè)字符串連接在一起的程序。 #include < iostream >#include < string >using namespace std;void

8、main()/使用string類(lèi)定義字符串，完成字符串連接string str1("C+"),str2("程序設(shè)計(jì)");string str3;str3 = str1+str2;/連接方式1cout<< str3<< endl;/使用char數(shù)組定義字符串，完成連接char c1 = "c+",c2 = "program"char c320;int i=0,k=0;for(i=0;i<20;i+)/初始化c3c3i='0'i=0;while(c1i!='0

9、9;)c3k=c1i;i+;k+;i=0;while(c2i!='0')c3k=c2i;i+;k+;cout<< c3<< endl;2.已知一個(gè)string的對(duì)象str的內(nèi)容為“We are here！”，使用多種方法輸出“h”。#include < iostream >#include < functional >#include < algorithm >#include < string >using namespace std;void main()string str1("We are

10、 here!");cout<< str17<< endl;/通過(guò)數(shù)組string str2=str1.substr(7,1);/通過(guò)得到子字符串cout<< str2<< endl;char *p=find(str1.begin(),str1.end(),'h');/通過(guò)find函數(shù)if(p)cout<<*p<< endl;第三章 一、填空題 1.函數(shù)原型聲明； 2.inline 3.對(duì)象、對(duì)象指針、引用 4.函數(shù)func返回引用 5.int *fun(char,int&); 二、單項(xiàng)選擇

11、題 1.A； 2.C； 3.C； 三、改錯(cuò)題 1.y = x * x - T; 錯(cuò)誤，T是類(lèi)型，不是變量，不能參加運(yùn)算； 2.y沒(méi)有類(lèi)型,并且x的類(lèi)型和template中的不一樣。 #include < iostream.h >template < class Type > Type max(Type x, Type y) return (x>y) ? (x) : (y) ; 3.函數(shù)change 的參數(shù)定義成了常量，只能使用參數(shù)，而無(wú)權(quán)修改他。 void change (string & s) s = s + "pig!" 四、編程題

12、 1.編寫(xiě)一個(gè)求方程ax2 + bx + c = 0的根 的程序，用3個(gè)函數(shù)分別求當(dāng)b2-4ac大于零、等于零、和小于零時(shí)的方程的根。要求從主函數(shù)輸入a,b,c的值并輸出結(jié)果。 #include < iostream.h >#include < math.h >void equation_1 (int a, int b, int c)double x1, x2, temp;temp = b*b - 4 * a * c;x1 = (-b + sqrt(temp) ) / (2 * a * 1.0);x2 = (-b - sqrt(temp) ) / (2 * a * 1.

13、0);cout<<"兩個(gè)不相等的實(shí)根"<< endl;cout<<"x1 = "<< x1<<", x2 = "<< x2<< endl;void equation_2 (int a, int b, int c)double x1, x2, temp;temp = b*b - 4 * a * c;x1 = (-b + sqrt(temp) ) / (2 * a * 1.0);x2 = x1;cout<<"兩個(gè)相等的實(shí)根"

14、<< endl;cout<<"x1 = "<< x1<<", x2 = "<< x2<< endl;void equation_3 (int a, int b, int c)double temp, real1, real2, image1, image2;temp = - (b*b - 4 * a * c);real1 = -b / (2 * a *1.0);real2 = real1;image1 = sqrt(temp);image2 = - image1;cout<&l

15、t;"兩個(gè)虛根"<< endl;cout<<"x1 = "<< real1<<" + "<< image1<<"j"<< endl;cout<<"x2 = "<< real2<<" + "<< image2<<"j"<< endl;void main()int a, b, c;double temp;c

16、out<<"輸入a,b,c的值"<< endl;cin>>a>>b>>c;cout<<"方程為："<< a<<"x*x+"<< b<<"x+"<< c<<" = 0"<< endl;temp = b*b - 4 * a * c;if(temp > 0)equation_1 (a, b, c);if(temp = 0)equation_2

17、 (a, b, c);if(temp < 0)equation_3 (a, b, c);2.定義函數(shù)up(ch)，如字符變量ch是小寫(xiě)字母就轉(zhuǎn)換成大寫(xiě)字母并通過(guò)up返回，否則字符ch不改變。要求在短小而完全的程序中顯示這個(gè)程序是怎樣被調(diào)用的。#include < iostream >using namespace std;char up (char c)if(c >= 97 && c <= 122)return (c - 32) ;elsereturn c;void main()int i;char c15 = 'A','v

18、','e','t','E','T','%','&','4','Y','e','i','','9',''for(i = 0 ; i < 15 ; i+)cout<< up(ci)<<", "cout<< endl;3.編寫(xiě)主程序條用帶實(shí)數(shù)r和整數(shù)n兩個(gè)參數(shù)的函數(shù)并輸出r的n次冪。#include < iost

19、ream.h >#include < math.h >double power(double a, int b)int i;double result = 1.0;for(i=0;i< b;i+)result = result * a;return result;void main()double r;int n;cout<<"r = "cin>>r;cout<<"n = "cin>>n;cout<< r<<"的"<< n<

20、;<"次冪是："<< power(r,n)<< endl;4.編寫(xiě)有字符型參數(shù)C和整形參數(shù)N的函數(shù)，讓他們顯示出由字符C組成的三角形。其方式為第1行有1個(gè)字符C，第2行有2個(gè)字符C ，等等。#include < iostream >using namespace std;void print_triangle(char c, int n)int i, j;for(i=0; i< n; i+)for(j=0; j<=i; j+)cout<< c;cout<< endl;void main()prin

21、t_triangle('a',10);5.編寫(xiě)一個(gè)ieqiu字符串長(zhǎng)度的函數(shù)，strlen（），再用strlen（）函數(shù)編寫(xiě)一個(gè)函數(shù)revers（s）的倒序遞歸程序，使字符串s逆序。#include < iostream >#include < string >using namespace std;int strlen(char *str)int len = 0;while(strlen != '0')len+;return len;void revers(char *b)char c; int j, len; len=strlen(b

22、); j=len/2-1; while(j>=0) c=*(b+j); *(b+j)=*(b+len-j-1); *(b+len-j-1)=c; j-; blen='0'void main()char str=""cout<< str<<"-的長(zhǎng)度："<< strlen(str)<< endl;cout<< str<< endl;/倒序前revers(str);/cout<< str<< endl;/倒序后6.用函數(shù)模板實(shí)現(xiàn)3個(gè)數(shù)值中按最

23、小值到最大值排序的程序。#include < iostream >using namespace std;template void sort(T a, T b, T c)T array3,temp;int i,j;array0 = a;array1 = b;array2 = c;for(i=0;i<3;i+)for(j=0;j<2;j+)if(arrayj>arrayj+1)temp = arrayj;arrayj = arrayj+1;arrayj+1 = temp;cout<< array0<< array1<< arra

24、y2<< endl;void main()sort(5,1,9);7.利用函數(shù)模板設(shè)計(jì)一個(gè)求數(shù)組元素中和的函數(shù)，并檢驗(yàn)之。#include < iostream >using namespace std;template <class T>T sum (T a,int n)int i;T s=0;for(i=0;i< n;i+)s = s + ai;return s;void main ()int a5=1,2,3,4,5;int s = sum(a,5);cout<< s<< endl;8.重載上題中的函數(shù)模板，使他能夠進(jìn)行兩

25、個(gè)數(shù)組的求和。#include < iostream >using namespace std;template T sum (T a, int n)int i;T s=0;for(i=0;i< n;i+)s = s + ai;return s;template /重載上面的模板T sum (T a, int n, T b, int m)return sum(a,n)+sum(b,m);void main ()int a5=1,2,3,4,5;int b10=1,2,3,4,5,6,7,8,9,10;int s1 = sum(a, 5);int s2 = sum(b, 10)

26、;int s3= sum(a, 5, b, 10);cout<< s1<< endl;cout<< s2<< endl;cout<< s3<< endl; 第四章一、填空題1.數(shù)據(jù)成員、成員函數(shù)； 2.類(lèi)、析構(gòu)函數(shù)不允許有參數(shù)和返回類(lèi)型（可是顯示地說(shuō)明參數(shù)為void）、一個(gè)類(lèi)有1個(gè)析構(gòu)函數(shù)； 3.fun:fun(fun &)、fun:fun(const fun &); 二、單項(xiàng)選擇題 1.C。2.C。3.沒(méi)又答案，應(yīng)該是A:A(void)、或A:A()。4.B。 5.C。 6.C。 7.D三、改錯(cuò)題 1.r

27、eturn m;-錯(cuò)誤，沒(méi)又定義變量m； 2.A.init(24,56);-錯(cuò)誤，沒(méi)有聲明對(duì)象A，init函數(shù)參數(shù)不對(duì)應(yīng)；Setx函數(shù)是int型但是沒(méi)有返回值 四、完成程序題 1.#include < iostream >using namespace std;class baseprivate :/私有數(shù)據(jù)成員int a, b;public :void init(int x, int y)/公有函數(shù)a = x;b = y;void print()cout<<"2 * "<< a<<" - "<<

28、; b<<" = "<<(2*a-b)<< endl;void main()base a;a.init(68,55);a.print();2.#include using namespace std;class Pointprivate : int m, n;public :Point(int, int);/整型變量，為參數(shù)的構(gòu)造函數(shù)Point(Point&);/復(fù)制構(gòu)造函數(shù)的原型print()cout<<"m = "<< m<<", n = "<&

29、lt; n<< endl;Point:Point(int a, int b)m = a;n = b;Point:Point(Point & t)/復(fù)制構(gòu)造函數(shù)的定義m = t.m;n = t.n;void main()Point a(10,89);Point b(a);a.print();b.print();五、程序分析題1.沒(méi)有結(jié)果，因?yàn)闆](méi)有main函數(shù)如果加main函數(shù)void main()base b(10, 20);輸出：初始化.10,20Destory.10,202.輸出：55六、編程題1.設(shè)計(jì)一個(gè)點(diǎn)類(lèi)Point，再設(shè)計(jì)一個(gè)矩形類(lèi)，矩形類(lèi)使用Point類(lèi)的兩個(gè)坐標(biāo)

30、點(diǎn)作為矩形的對(duì)角頂點(diǎn)。并可以輸出4個(gè)坐標(biāo)值和面積。使用測(cè)試程序驗(yàn)證程序。#include using namespace std;class Point/點(diǎn)類(lèi)private:int x, y;/私有成員變量，坐標(biāo)public :Point()/無(wú)參數(shù)的構(gòu)造方法，對(duì)xy初始化x = 0;y = 0;Point(int a, int b)/又參數(shù)的構(gòu)造方法，對(duì)xy賦值x = a;y = b;void setXY(int a, int b)/設(shè)置坐標(biāo)的函數(shù)x = a;y = b;int getX()/得到x的方法return x;int getY()/得到有的函數(shù)return y;class Rec

31、tangle/矩形類(lèi)private:Point point1, point2, point3, point4;/私有成員變量，4個(gè)點(diǎn)的對(duì)象public :Rectangle();/類(lèi)Point的無(wú)參構(gòu)造函數(shù)已經(jīng)對(duì)每個(gè)對(duì)象做初始化啦，這里不用對(duì)每個(gè)點(diǎn)多初始化了Rectangle(Point one, Point two)/用點(diǎn)對(duì)象做初始化的，構(gòu)造函數(shù)，1和4為對(duì)角頂點(diǎn)point1 = one;point4 = two;init();Rectangle(int x1, int y1, int x2, int y2)/用兩對(duì)坐標(biāo)做初始化，構(gòu)造函數(shù)，1和4為對(duì)角頂點(diǎn)point1.setXY(x1, y

32、1);point4.setXY(x2, y2);init();void init()/給另外兩個(gè)點(diǎn)做初始化的函數(shù)point2.setXY(point4.getX(), point1.getY() );point3.setXY(point1.getX(), point4.getY() );void printPoint()/打印四個(gè)點(diǎn)的函數(shù)cout<<"A：("<< point1.getX() <<"，"<< point1.getY() <<")"<< endl;c

33、out<<"B：("<< point2.getX() <<"，"<< point2.getY() <<")"<< endl;cout<<"C：("<< point3.getX() <<"，"<< point3.getY() <<")"<< endl;cout<<"D：("<< point4.

34、getX() <<"，"<< point4.getY() <<")"<< endl;int getArea()/計(jì)算面積的函數(shù)int height, width, area;height = point1.getY() - point3.getY();width = point1.getX() - point2.getX();area = height * width;if(area > 0)return area;elsereturn -area;void main()Point p1(-15, 5

35、6), p2(89, -10);/定義兩個(gè)點(diǎn)Rectangle r1(p1, p2);/用兩個(gè)點(diǎn)做參數(shù)，聲明一個(gè)矩形對(duì)象r1Rectangle r2(1, 5, 5, 1);/用兩隊(duì)左邊，聲明一個(gè)矩形對(duì)象r2cout<<"矩形r1的4個(gè)定點(diǎn)坐標(biāo)："<< endl;r1.printPoint();cout<<"矩形r1的面積："<< r1.getArea() << endl;cout<<"n矩形r2的4個(gè)定點(diǎn)坐標(biāo)："<< endl;r2.printPoi

36、nt();cout<<"矩形r2的面積："<< r2.getArea() << endl;2.使用內(nèi)聯(lián)函數(shù)設(shè)計(jì)一個(gè)類(lèi)，用來(lái)表示直角坐標(biāo)系中的任意一條直線并輸出它的屬性。#include < iostream.h >#include < math.h >class Lineprivate:int x1, y1, x2, y2;public :Line();Line(int =0, int =0, int =0, int=0 );void printPoint();double getLength();inline L

37、ine:Line(int a, int b, int c, int d)x1 = a;y1 = b;x2 = c;y2 = d;inline void Line:printPoint()cout<<"A："<< x1 <<", "<< y1 << endl;cout<<"B："<< x2 <<", "<< y2 << endl;inline double Line:getLength()doubl

38、e length;length = sqrt(x2-x1)*(x2-x1) + (y2-y1)*(y2-y1) );return length;void main()Line line(10,80,-10,12);line.printPoint();cout<< line.getLength() << endl;第五章 一、填空題1.常成員函數(shù)；2.常量成員函數(shù)；3.const二、單項(xiàng)選擇題1.B; 2.A; 3.C; 4.A;三、改錯(cuò)題1.static int getn()return number;錯(cuò)誤靜態(tài)成員函數(shù)，只允許訪問(wèn)靜態(tài)成員變量，number不是靜態(tài)成員變

39、量2.void main()test *two2 = new test(4, 5), new test(6 ,8);for( i=0; i<2; i+)delete twoi;四、完成程序題#include < iostream >using namespace std;class testint x;public :test(int a)x = a;int GetX()return x;void main()int i;/填空一，聲明變量itest *p, a23 = 1, 2, 3, 4, 5, 6;for( p=&a00, i=0; i<=6; i+, p

40、+)/填空2，初始化p，iif(p-a0)%3 = 0)cout<< endl;cout<< p->GetX() <<" "五、編程題1.聲明復(fù)數(shù)的類(lèi)，complex，使用友元函數(shù)add實(shí)現(xiàn)復(fù)數(shù)加法。#include < iostream >#include <complex>using namespace std;class Complexprivate:double real, image;public :Complex()Complex(double a,double b)real = a;image

41、= b;void setRI(double a, double b)real = a;image = b;double getReal()return real;double getImage()return image;void print()if(image>0)cout<<"復(fù)數(shù)："<< real <<" + "<< image <<"i"<< endl;if(image<0)cout<<"復(fù)數(shù)："<<

42、 real <<" - "<< image <<"i"<< endl;friend Complex add(Complex ,Complex);/聲明友元函數(shù);Complex add(Complex c1, Complex c2)/定義友元函數(shù)Complex c3;c3.real = c1.real + c2.real;/訪問(wèn)Complex類(lèi)中的私有成員c3.image = c1.image + c2.image;return c3;void main()Complex c1(19, 0.864), c2,

43、 c3;c2.setRI(90,125.012);c3 = add(c1, c2);cout<<"復(fù)數(shù)一："c1.print();cout<<"復(fù)數(shù)二："c2.print();cout<<"相加后："c3.print();2.例子5.8，114頁(yè)例子不錯(cuò)；3.編寫(xiě)一個(gè)程序，該程序建立一個(gè)動(dòng)態(tài)數(shù)組，為動(dòng)態(tài)數(shù)組的元素賦值，顯示動(dòng)態(tài)數(shù)組的值并刪除動(dòng)態(tài)數(shù)組。#include < iostream >using namespace std;void main()int i, n, temp=0;c

44、out<<"輸入數(shù)組大小:"cin>>n;double *array = new doublen; /用指針，動(dòng)態(tài)申請(qǐng)數(shù)組大小cout<<"給每個(gè)數(shù)組元素賦值："<< endl;for(i=0; i < n; i+)cout<<"array"<< i <<" = "cin>>temp;*(array+i) = temp;/給數(shù)組元素賦值cout<<"動(dòng)態(tài)數(shù)組個(gè)元素的值如下："<

45、< endl;for(i=0; i < n; i+)cout<<"array"<< i <<" = "<< arrayi << endl;/打印數(shù)組元素delete array;/釋放內(nèi)存4.定義一個(gè)Dog類(lèi)，它用靜態(tài)數(shù)據(jù)成員Dogs記錄Dog的個(gè)體數(shù)目，靜態(tài)成員函數(shù)GetDogs用來(lái)存取Dogs。設(shè)計(jì)并測(cè)試這個(gè)類(lèi)。#include < iostream >using namespace std;class Dogprivate:static int dogs;/靜態(tài)數(shù)據(jù)

46、成員，記錄Dog的個(gè)體數(shù)目public :Dog()void setDogs(int a)dogs = a;static int getDogs()return dogs;int Dog : dogs = 25;/初始化靜態(tài)數(shù)據(jù)成員void main()cout<<"未定義Dog類(lèi)對(duì)象之前：x = "<< Dog:getDogs() << endl; /x在產(chǎn)生對(duì)象之前即存在，輸出25Dog a, b;cout<<"a中x："<< a.getDogs() << endl;cout&l

47、t;<"b中x："<< b.getDogs() << endl;a.setDogs(360);cout<<"給對(duì)象a中的x設(shè)置值后："<< endl;cout<<"a中x："<< a.getDogs() << endl;cout<<"b中x："<< b.getDogs() << endl;第六章一、填空題 1.單一繼承； 2.private protected public 二、單項(xiàng)選擇 1

48、.C; 2.A; 3.C; 4.無(wú)答案;BCD中，構(gòu)造函數(shù)和析構(gòu)函數(shù)是都不會(huì)被繼承的 三、改錯(cuò)題 1.類(lèi)derived和base中均沒(méi)變量b，derived的構(gòu)造函數(shù)中的m(b)錯(cuò)誤；derived的構(gòu)造函數(shù)應(yīng)為：derived(int b) : base(b);2.Derived類(lèi)中重載show()方法void Show()Base1:Show();Base2:Show();四、編程題 1.設(shè)計(jì)一個(gè)基類(lèi)，從基類(lèi)派生圓柱，設(shè)計(jì)成員函數(shù)輸出它們的面積和體積；#include < iostream >using namespace std;class Basic/基類(lèi)protected

49、:double r;public :Basic() r = 0; Basic(double a):r(a);class Circular : public Basic/從基類(lèi)派生圓類(lèi)protected:double area;public :Circular(double a)r = a;area = area = 3. * r * r;double getArea()/返回圓面積return area;class Column : public Circular/從圓類(lèi)派生圓柱類(lèi)protected:double h;double cubage;public :Column(double a,

50、 double b) : Circular(a)h = b;cubage = getArea() * h;double getCubage()/返回圓柱體積函數(shù)return cubage;void main()Circular circular(45);Column column(12, 10);cout<<"圓的面積："<< circular.getArea() << endl;cout<<"圓柱的體積："<< column.getCubage() << endl;3.定義一個(gè)線段

51、類(lèi)作為矩形的基類(lèi)，基類(lèi)有起點(diǎn)和終點(diǎn)坐標(biāo)，有輸出左邊和長(zhǎng)度以及線段和x軸的夾角的成員函數(shù)。矩線段對(duì)象的兩個(gè)坐標(biāo)作為自己一條邊的位置，它具有另外一條邊，能輸出矩形的4個(gè)頂點(diǎn)坐標(biāo)。給出類(lèi)的定義并用程序驗(yàn)證它們的功能。#include < iostream > #include < cmath >using namespace std;class Point/點(diǎn)類(lèi)protected:double x, y;public :Point()Point(double a, double b)x = a; y = b;double getX()return x;double getY(

52、)return y;class Lineprotected:Point p1, p2;/Point對(duì)象做成員double length, angle;public:Line(double a, double b, double c, double d):p1(a, b), p2(c, d)/用兩對(duì)坐標(biāo)初始化線段init();Line(Point a, Point b)/用兩個(gè)點(diǎn)的對(duì)象初始化線段p1 = a; p2 = b;init();void init()/計(jì)算線段長(zhǎng)度，以及和x軸的夾角的度數(shù)double x1 = p1.getX(), y1 = p1.getY();double x2 =

53、p2.getX(), y2 = p2.getY();length = sqrt(x1-x2)*(x1-x2) + (y1-y2)*(y1-y2);angle = atan( (y2-y1) / (x2-x1) );angle = angle *180/3.;void printXY()cout<<"("<< p1.getX() <<","<< p1.getY() <<"); ("<< p2.getX() <<","<<

54、p2.getY() <<")"<< endl;void printLength()cout<<"線段長(zhǎng)度："<< length << endl;void printAngle()cout<<"與x軸的夾角："<< angle <<"°"<< endl;class Rectangle : public Lineprotected:Line *line;public:Rectangle(double a

55、, double b, double c, double d, double e, double f, double g, double h):Line(a,b,c,d)line = new Line(e,f,g,h);Rectangle(Point a, Point b, Point c, Point d) : Line(a, b)/4個(gè)點(diǎn)對(duì)象，初始化line = new Line(c, d);void printPoint()cout<<"矩形4個(gè)頂點(diǎn):n"printXY();line->printXY();void main()Point p1(0,

56、 0), p2(4, 3), p3(12, 89), p4(10, -50);Line l1(0,0,4,3);l1.printXY();l1.printLength();l1.printAngle();Line l2(p1, p2);l2.printXY();l2.printLength();l2.printAngle();Rectangle r1(12,45,89,10,10,23,56,1);r1.printPoint();Rectangle r2(p1, p2, p3, p4);r2.printPoint();4.基類(lèi)是使用極坐標(biāo)的點(diǎn)類(lèi)，從它派生一個(gè)圓類(lèi)，圓類(lèi)用點(diǎn)類(lèi)的左邊作圓心，圓周通

57、過(guò)極坐標(biāo)原點(diǎn)，圓類(lèi)有輸出圓心直、圓半徑和面積的成員函數(shù)。完成類(lèi)的設(shè)計(jì)并驗(yàn)證之。#include < iostream >#include < cmath >using namespace std;class Point/點(diǎn)類(lèi)protected:int x, y;public :Point();class Circular : public Point/圓類(lèi)，繼承點(diǎn)類(lèi)protected:double r, area;public :Circular(int a, int b)x = a;y = b;r = sqrt( x * x + y * y );area = 3. * r * r;void printPoint()cout<<"圓形直角坐標(biāo)：("<< x <<", "<< y <<")"<< endl;void printRadius()cout<<"圓的半徑:"<< r << endl;void printArea()cout<<"圓的面積:"<< area << endl;void mai