1. 下面程序的运行结果是____
#include<iostream>
using namespace std;
class Base
{public:
Base(){ cout << "0"; }
};
Class Base1: virtual Base
{public:
Base1(){ cout << "1"; }
};
Class Base2: virtual Base
{public:
Base2(){ cout << "2"; }
};
class Derived: public Base1, public Base2
{public:
Derived(){ cout << "3"; }
};
void main()
{ Derived obj;
}
A. 0123 B. 3120 C. 0312 D. 3012
答案：A
2. 写出程序运行结果
#include<iostream>
using namespace std;
int i = 0;
void fun()
{
{
static int i = 1;
std::cout << i++ << ',';
}
std::cout << i << ',';
}
int main()
{
fun(); fun();
return 0;
}
答案：1,0,2,0,
3. 下列程序中画线处应填如的语句是____
class Base
{public:
void fun(){ cout << "Base of fun" << endl; }
};
class Derived: public Base
{public:
void fun()
{
______ //调用基类的成员函数fun()
cout << "Derived of fun" << endl;
}
};
A. fun(); B. Base.fun();
C. Base::fun(); D. Base->fun() ;
答案：C
4. 写出程序运行结果
#include<iostream>
using namespace std;
class Base
{public:
int x;
void Print(){ cout << "Base::x is " << x << endl; }
};
class Derived1: public Base
{public:
void Print()
{ cout << "Derived1::x is " << x << endl;
}
};
class Derived2: private Base
{public:
Derived2(){ Base::x = 4; }
int x;
void Print()
{ cout << "Derived2's Base::x is " << Base::x << endl;
cout << "Derived2::x is " << x << endl;
}
};
void main()
{ Base objB;
Derived1 objD1;
Derived2 objD2;
objD2.x = 1 + (objD1.x = 1 + (objB.x = 1));
objB.Print();
objD1.Print();
objD2.Print();
}
答案：Base::x is 1
Derived1::x is 2
Derived2’s Base::x is 4
Derived2::x is 3
5. 写出程序运行结果
#include<iostream>
using namespace std;
class A
{public:
A(){ cout << "constructor of A" << endl; }
~A(){ cout << "destructor of A" << endl; }
};
class B
{public:
B(){ cout << "constructor of B" << endl; }
~B(){ cout << "destructor of B" << endl; }
};
int main()
{ B b;
static A a;
}
答案：constructor of B
constructor of A
constructor of B
constructor of A
6. 写出程序运行结果
#include<iostream>
using namespace std;
class Coord
{public:
Coord(int i = 0, int j = 0){ x = i; y = j; }
void Print(){ cout << "x=" << x << ", y=" << y << endl; }
friend Coord operator++(Coord op);
private:
int x, y;
};
Coord operator ++(Coord op)
{ ++op.x;
++op.y;
return op;
}
void main()
{ Coord obj(1, 2);
obj.Print();
++obj;
obj.Print();
}
答案：x = 1, y = 2
x = 1, y = 2
7. 写出程序运行结果
#include <iostream>
using namespace std;
class Expt{};
class Expt1: public Expt{
public: Expt1() { cout<<"Expt1 的构造函数被调用。"<<endl; }
Expt1(Expt1 & e) {cout<<"Expt1 的拷贝构造函数被调用。"<<endl; }
~Expt1() { cout<<"Expt1 的析构函数被调用。"<<endl; }
};
class Expt2: public Expt1 {
public: Expt2() { cout<<"Expt2 的构造函数被调用。"<<endl; }
Expt2(Expt2 & e) { cout<<"Expt2 的拷贝构造函数被调用。"<<endl; }
~Expt2() { cout<<"Expt2 的析构函数被调用。"<<endl; }
};
void MyFunc() { Expt1 e; throw e; }
void main() {
try {
cout << "在try块中，调用MyFunc()。" << endl;
MyFunc();
cout << "在try块中，MyFunc()执行结束。" << endl;
}
catch( Expt E ) { cout << "捕获到Expt类型异常。"<<endl; }
catch( Expt2 E ) { cout << "捕获到Expt2类型异常。"<<endl; }
cout << "回到main函数。" << endl;
}
答案：在try块中，调用MyFunc()。
Expt1 的构造函数被调用。
Expt1 的拷贝构造函数被调用。
Expt1 的析构函数被调用。
捕获到Expt类型异常。
Expt1 的析构函数被调用。
回到main函数。
8. 下面的程序有什么错误？
class MyClass
{
public:
void MyClass(int a){ x = a; }
int f(int a, int b){ x = a; y = b; }
int f(int a, int b, int c = 0){ x = a; y = b; z = c; }
static void g(){ x = 10; };
private:
int x, y, z;
};
答案：构造函数不能有返回值和返回值类型；静态函数g不能直接访问非静态数据成员x。
9. 写出程序运行结果
#include<iostream>
using namespace std;
class Shape{
public:
Shape() { cout<<"Shape 的构造函数被调用。"<<endl; }
void Display() { cout<<"Shape 的显示函数被调用。"<<endl; }
virtual ~Shape() { cout<<"Shape 的析构函数被调用。"<<endl; }
};
class Rectangle: public Shape {
public: Rectangle () {
Side=Hight=0;
cout<<"Rectangle 的默认构造函数被调用。"<<endl;
}
Rectangle(int xx,int yy) {
Side=xx; Hight=yy;
cout<< "Rectangle 的构造函数被调用。"<<endl;
}
void Display() {
cout<<" Rectangle 的边长和高为："<<Side<<","<<Hight<<endl;
}
~Rectangle() { cout<<"Rectangle 的析构函数被调用。"<<endl; }
int GetSide() {return Side;}
int GetHight() {return Hight;}
private:
int Side, Hight;
};
void main()
{
Shape *ptr1 = new Rectangle[2];
(*(ptr1+1)).Display();
delete [] ptr1;
}
答案：Shape的构造函数被调用。
Rectangle的默认构造函数被调用。
Shape的构造函数被调用。
Rectangle的默认构造函数被调用。
Shape的显示函数被调用。
Rectangle的析构函数被调用。
Shape的析构函数被调用。
Rectangle的析构函数被调用。
Shape的析构函数被调用。
10. 写出程序运行结果
#include<iostream>
using namespace std;
template<class T>
class Sample
{private:
T n;
public:
Sample(T i){ n = i; }
void operator++();
void disp(){ cout << "n = " << n << endl; }
};
template<class T>
void Sample<T>::operator++()
{ n += 1;
}
void main()
{ Sample<char> s('a');
s++;
s.disp();
}
答案：n = b
11. 写出程序运行结果
#include <iostream>
using namespace std;
char* increase(char* ch) {return ++ch;}
char& increase(char& ch) {return ++ch;}
int main(){
char buf[16] = "IloveC++!";
char* p = buf;
for (int i = 0; i < 4; i++) {
p = increase(p);
increase(*p);
}
cout << buf << endl;
return 0;
}
答案：ImpwfC++!
12. 写出程序运行结果
#include<iostream>
using namespace std;
class Sample
{
public:
int x, y;
Sample(int a = 0, int b = 0){ x = a; y = b; }
friend void square_x(Sample &s){ s.x = s.x * s.x; }
void disp(){ cout << "x = " << x << ", y = " << y << endl; }
};
void main()
{
Sample s(2, 3);
square_x(s);
s.disp();
}
答案：x = 4, y = 3
13. 写出程序运行结果
#include<iostream>
using namespace std;
class A
{
int num;
public:
A(int i){ num = i; }
A(A &a){ num = a.num++; }
void print(){ cout << num; }
};
void main()
{
A a(1), b(a);
a.print();
b.print();
}
答案：21
14. 写出程序运行结果
#include<iostream>
using namespace std;
class Base
{public:
int n;
Base(int x){ n = x; }
virtual void set(int m){ n = m; cout << n << ' '; }
};
class DerivedA: public Base
{public:
DerivedA(int x): Base(x){ }
void set(int m){ n += m; cout << n << ' '; }
};
class DerivedB: public Base
{public:
DerivedB(int x): Base(x){ }
void set(int m){ n += m; cout << n << ' '; }
};
int main()
{ DerivedA da(1);
DerivedB db(3);
Base * pBase;
pBase = &da;
pBase->set(1);
pBase = &db;
pBase->set(2);
}
答案：2 5
15. 写出程序运行结果
#include <iostream>
using namespace std ;
class Base
{public:
virtual void fun(int a) { cout << "Base: " << a << endl; }
void fun(char *p) { cout << "Base: " << p << endl; }
void fun() { cout << "Base: no parameter!" << endl; }
};
class Derived: public Base
{public:
void fun(int a) { cout << "Derived:" << a << endl; }
void fun(char *p) { cout << "Derived:" << p << endl; }
};
void main()
{ Derived* pd = new Derived;
Base *pb = pd;
pb->fun(); pb->fun(0); pb->fun("c++");
pd->fun(1); pd->fun("object");
}
答案：Base: no parameter!
Derived:0
Base: c++
Derived:1
Derived:object
16. 写出程序运行结果
#include<iostream>
using namespace std;
class Sample
{
public:
int x, y;
Sample(int a = 0, int b = 0){ x = a; y = b; }
~Sample(){ cout << "x = " << x << ", y = " << y << endl; }
};
void main()
{
Sample s;
s.~Sample();
}
答案：x = 0, y = 0
x = 0, y = 0
17. 写出程序运行结果
#include<iostream>
Using namespace std;
class First
{protected:
int first;
public:
First(int f = 0){ first = f; }
void show(){ cout << first << endl; }
};
class Second: public First
{private:
int second;
public:
Second(int f, int s): First(f), second(s) { }
void show(){ cout << first << " " << second << endl; }
};
int main()
{
Second s(5, 3);
s.show();
}
A. 5 3 B. 3 C. 5 D. 3 5
答案：A
18. 写出程序运行结果
#include<iostream>
using namespace std;
class Base
{int n;
public:
Base(int a)
{ cout << "constructing base class" << endl;
n = a;
cout << "n = " << n << endl;
}
~Base(){ cout << "destructing base class" << endl; }
};
class Derived: public Base
{ Base base;
int m;
public:
Derived(int a, int b, int c) : Base(a), base(c)
{ cout << "constructing derived class" << endl;
m = b;
cout << "m = " << m << endl;
}
~Derived(){ cout << "destructing derived class" << endl; }
};
void main(){ Derived d(1, 2, 3); }
答案：constructing base class
n = 1
constructing base class
n = 3
constructing derived class
m = 2
destructing derived class
destructing base class
destructing base class
19. 写出程序运行结果
#include <iostream>
using namespace std;
class B1 {
public: B1(int i) {cout<<"B1 的构造函数被调用:"<<i<<endl;}
~B1() {cout<<"B1 的析构函数被调用。"<<endl;}
};
class B2 {
public: B2(int j) {cout<<"B2 的构造函数被调用:"<<j<<endl;}
~B2() {cout<<"B2 的析构函数被调用。"<<endl;}
};
class C: public B2, public B1 {
public:
C(int a, int b, int c, int d):B1(a),memberB2(d),memberB1(c),B2(b) {
cout<<"C 的构造函数被调用。"<<endl;
}
~C() { cout<<"C 的析构函数被调用。"<<endl;}
private:
B1 memberB1; B2 memberB2;
};
void main(){
C obj(1,2,3,4);
}
答案：B2的构造函数被调用：2
B1的构造函数被调用：1
B1的构造函数被调用：3
B2的构造函数被调用：4
C的构造函数被调用。
C的析构函数被调用。
B2的析构函数被调用。
B1的析构函数被调用。
B1的析构函数被调用。
B2的析构函数被调用。
20. 写出程序运行结果
#include<iostream>
using namespace std;
void func(int a)
{
static int m = 0;
m += a;
cout << m << " ";
}
void main()
{
int k = 6;
func(k);
func(k);
cout << endl;
}
答案：6 12
21. 下面程序的输出是____
#include<iostream>
using namespace std;
class Sample
{
public:
int x, y;
Sample(int a = 0, int b = 0){ x = a; y = b; }
~Sample(){ cout << "x = " << x << ", y = " << y << endl; }
};
void main()
{
Sample s;
exit(0);
}
答案：（不输出）
22. 写出程序运行结果
#include <iostream>
using namespace std;
class point {
protected:
int x, y;
public:
point(int xx, int yy) {
x = xx, y = yy;
cout << "construct point: " << x << "," << y << endl;
}
~point() { cout << "destroy point" << endl;}
};
class circle {
protected:
point center;
int radius;
public:
circle(int x, int y, int r):center(x, y),radius(r) {
cout << "construct circle: " << radius << endl;
}
~circle(){ cout << "destroy circle " << endl;}
};
int main() {
circle c(1,2,3);
return 0;
}
答案：construct point:1,2
construct circle:3
destroy circle
destroy point
23. 下面程序的执行结果是：
#include<iostream>
using namespace std;
class Sample
{ int x;
public:
Sample(int a)
{ x = a;
cout << "constructing object: x = " << x << endl;
}
};
void fun(int n)
{ static Sample obj(n);
}
void main()
{ fun(1); fun(10);
}
答案：constructing object: x = 1
24. 下面程序的执行结果是____
#include<iostream>
using namespace std;
class Sample
{
public:
int x, y;
void disp(){ cout << "x = " << x << ", y = " << y << endl; }
};
void main()
{
int Sample::*pc;
Sample s;
pc = &Sample::x;
s.*pc = 10;
pc = &Sample::y;
s.*pc = 20;
s.disp();
}
答案：x = 10, y = 20
25. 有以下程序：
#include<iostream>
using namespace std;
class MyClass
{
public:
MyClass(int n){ number = n; }
MyClass(MyClass & other){ number = other.number; }
~MyClass(){}
private:
int number;
};
MyClass fun(MyClass p)
{
MyClass temp(p);
return temp;
}
int main()
{
MyClass obj1(10), obj2(0);
MyClass obj3(obj1);
obj2 = fun(obj3);
return 0;
}
程序执行时，MyClass的拷贝构造函数被调用了几次？
答案：4次
26. 有以下定义：
class Point
{
public:
Point(int x = 0, int y = 0){ _x = x; _y = y; }
void Move(int xOff, int yOff)
{ _x += xOff; _y += yOff; }
void Print() const
{ cout << '(' << _x << ',' << _y << ')' << endl; }
private:
int _x, _y;
};
下列语句中会发生编译错误的是____
A. Point pt; pt.Print();
B. const Point pt; pt.Print();
C. Point pt; pt.Move(1, 2);
D. const Point pt; pt.Move(1, 2);
答案：D
27. 写出程序运行结果
#include<iostream>
using namespace std;
char *x[] = {"first", "second", "third"};
void fun(char *z[])
{
cout << *++z << endl;
}
int main()
{
char **y;
y = x;
fun(y);
return 0;
}
答案：second
28. 写出程序运行结果
#include <iostream>
using namespace std;
class counter {
protected:
static int count;
int id;
public:
counter() {
id = ++ count;
cout << "id = " << id << ", count = " << count << endl;
}
};
int counter::count = 0;
static counter c[3];
int main() {
cout << "initialize program" << endl;
return 0;
}
答案：id=1,count=1
id=2,count=2
id=3,count=3
initialize program
29. 写出程序运行结果
#include <iostream>
using namespace std;
class Expt{};
class Expt1: public Expt{
public: Expt1() { cout<<"Expt1 的构造函数被调用。"<<endl; }
Expt1(Expt1 & e) {cout<<"Expt1 的拷贝构造函数被调用。"<<endl; }
~Expt1() { cout<<"Expt1 的析构函数被调用。"<<endl; }
};
class Expt2: public Expt1 {
public: Expt2() { cout<<"Expt2 的构造函数被调用。"<<endl; }
Expt2(Expt2 & e) { cout<<"Expt2 的拷贝构造函数被调用。"<<endl; }
~Expt2() { cout<<"Expt2 的析构函数被调用。"<<endl; }
};
void MyFunc() { Expt1 e; throw e; }
void main() {
try {
cout << "在try块中，调用MyFunc()。" << endl;
MyFunc();
cout << "在try块中，MyFunc()执行结束。" << endl;
}
catch( Expt E ) { cout << "捕获到Expt类型异常。"<<endl; }
catch( Expt2 E ) { cout << "捕获到Expt2类型异常。"<<endl; }
cout << "回到main函数。" << endl;
}
答案：在try块中，调用MyFunc()。
Expt1 的构造函数被调用。
Expt1 的拷贝构造函数被调用。
Expt1 的析构函数被调用。
捕获到Expt类型异常。
Expt1 的析构函数被调用。
回到main函数。
30. 有如下动态数组模板类Array的声明，请在空格处填入最合适的内容。
_(1)_ <class T>
class Array
{protected:
int size; //动态数组的长度
(2) elements; //动态数组的首地址
public：
Array(int i);
(3) ~Array(); //析构函数
Array( (4) a); //拷贝构造函数
(5) operator[](int index); //重载下标运算符
(6) ostream & operator <<(ostream &o, Array & a);
};
(1) 空格(1)处应该填写 【 】
A. virtual B. template C. void D. class
(2) 空格(2)处应该填写 【 】
A. T * B. T C. int * D. int
(3) 空格(3)处应该填写 【 】
A. void B. int C. virtual D. template
(4) 空格(4)处应该填写 【 】
A. Array B. Array * C. Array & D. const Array &
(5) 空格(5)处应该填写 【 】
A. T B. T * C. T & D. void
(6) 空格(6)处应该填写 【 】
A. friend B. const C. virtual D. void
答案：B A C D C A