艾默生软件工程师笔试题和面试题答案

思而思学网

1.考察虚继承内存体系

class A

{

public:

A() { cout<<"Construct A"<

~A() { cout<<"Destruct A"<

void speak() { cout<<"A is speaking!"<

};

class B:public virtual A

{

public:

B() { cout<<"Construct B"<

~B() { cout<<"Destruct B"<

};

class C:public virtual A

{

public:

C() { cout<<"Constuct C"<

~C() { cout<<"Destruct C"<

};

class D:public B, public C

{

public:

D(){ cout<<"Constsruct D"<

~D(){ cout<<"Destruct D"<

};

int main()

{

D p = new D();

p->speak();

delete p;

}

输出:

Construct A

Construct B

Constuct C

Constsruct D

A is speaking!

Destruct D

Destruct C

Destruct B

Destruct A

2.考察非虚析构函数这道题

class Parent

{

public:

Parent(){cout<<"Parent construct"<

~Parent(){ cout<<"Parent destruct "<

};

class Child : public Parent

{

public:

Child() { cout<<"Child construct "<

~Child() {cout<<"child destruct"<

};

int main()

{

Parent p;

Child c = new Child();

p = c;

delete p; // 因为析构函数是非 virtual 的,故析构的时候按照指针的类型进行析构

}

输出:

Parent construct

Child Construct

Parent destruct

3.考察初始化列表的写法

class A

{

public:

A(int x, int y, int z):a=x,b=y,c=z {} (1)

A(int x, int y, int z):a(x),b(y),c(z){} (2)

private:

int a;

int b;

int c;

};

int main()

{

A a(1,2,3);

}

第 1 种写法是错误的,第 2 种正确。

4.考察拷贝构造函数和赋值的区别。

class A

{

public:

A() { cout<<"Construct A by default"<

A(const A& a) { cout<<"consttuct A by copy"<

A& operator =(const A& a) { cout<<"cosnt A by operator ="<

~A() { cout<<"Destruct A"<

};

int main()

{

A a;

A b=a; //调用拷贝构造函数

A c(a); //调用拷贝构造

A d;

d=a; //赋值

}

输出:

Construct A by default //构造对象 a

consttuct A by copy //拷贝构造 b

consttuct A by copy //拷贝构造 c

Construct A by default //构造 a

cosnt A by operator = //赋值 d=a

Destruct A

Destruct A

Destruct A

Destruct A

5.考察函数指针

voidfunc(char a)

{

cout<

}

int main()

{

void (fp)(char); //填空处

fp = func; //函数名func相当于函数的地址,将其赋给函数指针fp

char s="helloc";

fp(s);

}

热门推荐

最新文章