c++
C++是一门强大的面向对象编程语言，由C语言发展而来，”++“意为更进一步发展，C++充分吸收了C语言的优点，同时汲取了面向对象的编程思想，其后拥有STL库的强大支撑，具有封装、继承、多态三大特性，常以高效能著称。
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有如下输出语句：cout<<setw（5）<<fixed<<setprecigion(3）<<3.1415926；此语句的输出结果是（ ）。
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已知类MyClass的定义如下：class MyClass { private : int num ; public : MyClass ( int d ) : num ( d ) { } MyClass ( const MyClass& original ) : num ( original . num ) { } friend void print ( MyClass c ) { cout << c.num } } ;且有如下程序段：MyClass c(5) ; MyClass *p1; p1=&c; print(*p1) ; print(c) ;运行这个程序段的过程中，对类MyClass的复制构造函数的调用次数是 （ ）。
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已知类Test的定义如下：class Test{ private : static int num ; public : void print ( int num ) { cout << ++ num ; cout << ++ this -> num; } }; int Test::num=0;且有如下程序段：int main(){ Test t1,t2; t1.print(0); t2.print(1); return 0; }运行这个程序段的输出是（ ）。
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已知类CC和函数test的定义如下：class CC { public : CC( ) { cout << '1'; } ~CC( ) { cout << '0'; } }; void test ( CC c ) { cout << '2'; }且有如下main函数：int main(){ CC c; test(c); return 0; }运行这个main函数的输出是（ ）。
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已知类AA和BB的定义如下：class AA { public: AA(){cout<<'0';} ~AA(){cout<<'1';} }; class BB:public AA { public: BB(){cout<<'2';} ~BB(){cout<<'3';} };且有如下主函数定义：int main(){ BB b; return 0; }运行这个main函数的输出是（ ）。
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已知类Base、Middle和Derived的定义如下：class Base { public : virtual void foo ( ) { cout << 'a'; } } ; class Middle : public Base { public : void foo ( ) { cout << 'b'; } } ; class Derived : public Middle { public : void foo ( ) { cout << 'c'; } } ;且有如下程序段：Base * p1; Middle * p2; Derived d; p1 = &d; p1 -> foo( ); p2 = &d; p2 -> foo( );运行这个程序段的输出是（ ）。
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类Base及其派生类Derived的定义如下：class Base { private : int a ; public : int b ; friend class Derived ; } ; class Derived : public Base { public : void foo( ) { a = 0;//① b = 0;//② } } ;则下列说法正确的是（ ）。
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已知类Time的定义如下：class Time { //时间类 private: int hour , minute , second ;//时、分、秒 public : Time ( int h , int m , int s ) : hour( h ), minute( m ), second( s ) { } ____________{ switch ( index ) { case 0 : return hour; case 1: return minute; default: return second; } } };其中横线处应为下标访问运算符[]的重载函数的函数头，横线处应填入 的代码是（ ）。
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已知类Array的定义如下：class Array { public : int data[ 2 ]; Array( int n = 0 ) { int start ; if ( n <= 1 ) start = n - 1; else start = n; data[ 0 ] = start ; data[ 1 ] = start + 1 ; } };且有如下程序段：Array arr(2); cout<<arr.data[0]<<arr.data[1];则执行这个程序段的输出是（ ）。
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有如下定义： int a[5]= 1,3,5,7,9）,* p=a； 下列表达式中不能得到数值5的是（ ）。
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下列语句分别是不同程序中的第一个输入输出语句，若去掉其中的“<<left”，输出效果将发生变化的是（ ）。
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有如下程序：#include <iostream> using namespace std; class GA{ public: virtual int f(){return 1;} }; class GB: public GA{ public: virtual int f(){return 2;} }; void show(GA g){cout<<g.f();} void display(GA &g){cout<<g.f();} int main(){ GA a; show(a); display(a); GB b; show(b); display(b); Return 0; }运行时的输出结果是（ ）。
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程序阅读题1、#include <iostream.h> class B { public: B(){} B(int i,int j){a=i;b=j;} void printb() {cout<<"a="<<a<<",b="<<b<<endl;} private: int a,b; }; class A { B c; public: A(){} A(int i,int j):c(i,j){} void printa(){c.printb();} }; int main() {A a(7,8); a.printa(); }2、#include <iostream.h> class CArray {int *m_pArray; int m_iSize; public: CArray(int iArray[],int iSize) {m_pArray=iArray; m_iSize=iSize; } int GetSize() {return m_iSize;} int &operator[](int i) {return m_pArray[i];} }; int main() {int s[]={3,7,2,1,5}; CArray oArray(s,5); oArray[0]=9; for(int i=0;i<5;i++) cout<<oArray[i]<<" "; cout<<endl; }3、#include <iostream.h> #include <math.h> template <class T> class TAdd {T x,y; public: TAdd(T a,T b){x=a,y=b;} T add(){return x+y;} }; int main() {TAdd<int> A(5,6); TAdd<double> B(2.4,5.8); cout<<"s1="<<A.add()<<endl; cout<<"s2="<<B.add()<<endl; }4、#include <iostream.h> class base { public: void who(){cout<<"base class"<<endl;} }; class derive1:public base { public: void who(){cout<<"derive1 class"<<endl;} }; class derive2:public base { public: void who(){cout<<"derive2 class"<<endl;} }; int main() {base obj1,*p; derive1 obj2; derive2 obj3; p=&obj1; p->who(); p=&obj2; p->who(); p=&obj3; p->who(); obj2.who(); obj3.who(); }5、#include <iostream> #include <cmath> #include <stdexcept> using namespace std; double area(double a, double b, double c) { if (a <= 0 || b <= 0 || c <= 0) throw invalid_argument("the side length should be positive"); if (a + b <= c || b + c <= a || c + a <= b) throw invalid_argument("the side length should fit the triangle inequality"); double s = (a + b + c) / 2; return sqrt(s * (s - a) * (s - b) * (s - c)); } int main() { double a, b, c;cin >> a >> b >> c; //输入1 2 4 try { double s = area(a, b, c); cout << "Area: " << s << endl; } catch (exception &e) { cout << "Error: " << e.what() << endl; } }
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请在下面程序的横线处填上适当内容，以使程序完整,并使程序的输出为:10+10i#include <iostream.h> class complex { int x,y; public:complex(){} complex(int i,int j) {x=i; y=j;} complex operator+(complex &p) {________(1)_______;} void show() {cout<<x<<"+"<<y<<"i";} }; int main() {complex p1(5,8),p2(5,2),p3; ________(2)_______; p3.show();
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请在下面程序的横线处填上适当字句，以使程序完整,并使程序的输出为(1,2)5,6(6,9)#include <iostream.h> class A { public: A(int i,int j){a=i;b=j;} void move(int x,int y){ ____(1)______;b+=y;} void show(){cout<<"("<<a<<","<<b<<")"<<endl;} private: int a,b; }; class B:private A { public: B(int i,int j,int k,int l):A(i,j){x=k;y=l;} void show(){cout<<x<<","<<y<<endl;} void fun(){move(3,5);} void fl(){____(2)______;} private:int x,y; }; int main() {A e(1,2); e.show(); B d(3,4,5,6); d.fun(); d.show(); d.fl(); }
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利用函数模板，设计求一个数组元素之和的函数sum和两个数组元素之和的函数sum，请在下面程序的横线处填上适当内容，以使程序完整,并使程序的输出为:数组a之和:15数组b之和:55两数组之和:70#include <iostream.h> template <class T> T sum (T a[],int n) {int i; T s=0; for(i=0;i<n;i++) s+=a[i]; return s; } template <class T> T sum(______________(1)____________) { return ______________(2)____________; } int main() {int a[5]={1,2,3,4,5}; int b[10]={1,2,3,4,5,6,7,8,9,10}; int s1=sum(a,5); int s2=sum(b,10); int s3=sum(a,5,b,10); cout<<"数组a之和:"<<s1<<endl; cout<<"数组b之和:"<<s2<<endl; cout<<"两数组之和:"<<s3<<endl; }
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请在下面程序的横线处填上适当内容，以使程序完整,并使运行结果为：HellohELLO#include <iostream.h> #include <string.h> class Words {char *str; public: Words(char *s) {str=new char[strlen(s)+1]; strcpy(str,s); } void disp(){cout<<str<<endl;} char operator[](int i) {if(str[i]>='A'&&str[i]<='Z') return char(str[i]+32); else if(str[i]>='a'&&str[i]<='z') return char(str[i]-32); else return str[i]; } }; int main() {int i;char *s="Hello"; Words word(s); ______________(1)____________; for (i=0;i<strlen(s);i++) ______________(2)____________; cout<<endl; }
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程序阅读题1、#include <iostream> using namespace std; int& element(int x[],int index) { return x[index+1]; } void main() { int a[]={3,7,2,1,5}; element(a,3)=9; for(int i=0;i<5;i++) cout<<a[i]<<’’; }2、#include<iostream> using namespace std; class A { int num; public: A() { num=0;cout<<"A default constructor"<<endl;} A(int n) {num=n;cout<<”A constructor,num=”<<num<<endl;} ~A() {cout<<"A destructor,num="<<num<<endl;} }; void main() { A a,*p; p=new A(2); a=*p; delete p; cout<<”Exiting main”<<endl; }3、#include<iostream> using namespace std; class Format { public: virtual void header() {cout<<"This is a head"<<endl; }virtual void footer() {cout<<"This is a footer"<<endl;} virtual void body() {cout<<"This is a body"<<endl;} void display() {header();body();footer();} }; class MyFormat:public Format { public: void header() {cout<<"This is my header"<<endl;} void footer() {cout<<"This is my footer"<<endl;} }; void main() { Format * p; p=new Format; p->display(); delete p; p=new MyFormat; p->display(); delete p; }4、从键盘输入8 4 3 1 9 6 1 1 2 5，给出程序的输出结果。#include<iostream> #include<vector> #include<stack> #include<iterator> using namespace std; main() { vector<int> v; stack<int> s; int i,n,x; cin>>n; for(i=0;i<n;i++) { cin>>x; v.push_back(x); } for(vector<int>::iterator p=v.begin();p!=v.end();p++) if(*p%2==0) s.push(*p); while(!s.empty()) { cout<<s.top()<<endl; s.pop(); } }5、#include<iostream> #include<exception> using namespace std; class Fract { int den,num; public: Fract(int d=0,int n=1) { if(n==0) throw exception("divided by zero"); den = d;num=n; } int& operator[](int index) { if(index<0||index>1) throw exception("index out of range"); if(index==0) return den; if(index==1)return num; } void show() { cout<<den<<"/"<<num<<endl;} }; void main() { try { Fract f(0,2); f.show(); cout<<f[1]<<"/"<<f[2]<<endl; } catch(exception e) { cout<<e.what()<<endl; } }
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下面程序通过把类Distance声明为类Point的友元类来实现计算两点之间的距离。请在下面程序的横线处填上适当字句，以使程序完整。#include<iostream> #include<cmath> using namespace std; class Point { double X,Y; public: Point(double x,double y) {X=x;Y=y;} ____________(1)____________; }; class Distance { public: double Dis(Point& p1,Point& p2); { double t; ____________________(2)___________________; return t; } } void main() { Point p(10,10),q(20,20); Distance d; cout<<d.Dis(p,q)<<endl; }
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请在下面程序的横线处填上适当字句，以使程序完整,并使程序的输出为8。#include<iostream.h> template<class T> void fun(___________(1)___________) { t=x[0]; for(int i=0;i<n;i++) if(a[i]>t) t=a[i]; } void main() { int a[]={3,5,8,4,6}; int m; fun(a,5,__(2)____); cout<<m<<endl; }