There are no instanced of A that will become eligible for garbage collection.
Explicitly setting myA to null marks that instance to be eligible for garbage collection.
Any call on tryIt() causes the private instance of A to be marked for garbage collection.
Private instances of A become eligible for garbage collection when instances of Alpha become eligible for garbage collection.
第1题:
下面程序输出的结果为
#include"iostream.h"
class A
{
public:
A( ){cout<<"CLASS A"<<endl;}
~A( ){}
};
class B:public A
{
public:
B( ){cout<<"CLASS B"<<endl;}
~B( ){}
};
void main( )
{
A*p;
p=new B;
B *q;
q=new B;
}
A.CLASS A CLASS B
B.CLASS A CLASS B CLASS B
C.CLASS A CLASS B CLASS A CLASS B
D.CLASS A CLASS B CLASS B CLASS B
第2题:
有以下程序: #include <iostream> #include <string> using namespace std; class Y; class X { private: int x; char *strx; public: X(int a, char *str) { x=a; strx=new char[strlen(str)+1]; strcpy(strx,str); } void show(Y &ob) ; }; class Y { private: int y; char *stry; public: Y(int b,char *str) { y=b; stry=new char[strlen(str)+1]; strcpy(stry, str); } friend void X: :show(Y &ob) ; }; void X: :show(Y &ob) { cout<<strx<<", "; cout<<ob, stry<<end1; } int main ( ) { X a(10,"X"); Y b (20, "Y"); a. show(B) ; return 0; } 执行后的输出结果是( )。
A.X,Y
B.a,b
C.X,X
D.Y,Y
第3题:
下面这个程序的结果是
#include<iostream.h>
class A
{
private:
int a;
public:
void seta( ) ;int geta( ) ;};
void A: :seta( )
{ a=1;}
int A: :geta( )
{ retum a;}
class B
{ private:
int a;
public:
void seta( ) ;int geta( ) ;};
void B: :seta( )
{a=2;}
int B: :geta( )
{return a;}
class C: public A,public B
{ private:
int b;
public:
void display( ) ;};
void C: :display( )
{ int b=geta( ) ;
cout < < b;}
void main( )
{ C c;
c. seta( ) ;
c. display( ) ;}
A.1
B.2
C.随机输出1或2
D.程序有错
第4题:
public class Alpha{ private static Character() ids; public static void main( String[] args){ ids = new Character[args.length]; for (int i=0; i
第5题:
此题为判断题(对,错)。
第6题:
类class one 在声明func 成员函数时发生错误,出错原因是【 】。
Class one
{
private:
int a;
public:
void func(two& )
};
class two
{
private:
int b;
friend void one: :func(two & );
};
void one: : func(two& r)
a=r.b;
}
第7题:
下面程序输出的结果为( )。 #inClUde”iostream.h” Class A {public: A(){cout<<“CLASS A”<<endl;} ~A()<)}; class B:public A {public: B(){cout<<”CLASSB”<<endl;} ~B(){}}; void main() {A*p; p=new B; B *q; q=new B;}
A.CLASS A CLASS B
B.CLASS A CLASS B CLASS B
C.CLASS A ClASS B
D.CLASS A CLASS B CLASS A CLASS B CLASS B CLASS B
第8题:
下面程序输出的结果为 #include"iostream.h" class A { public: A(){cout<<"CLASSA"<<endl;} ~A() {} }; class B:public A { public: B(){cout<<"CLASSB"<<endl;} ~B() {} }; void main() { A * p; p=new B; B *q; q=new B; }
A.CLASS A CLASS B
B.CLASS A CLASS B CLASS B
C.CLASS A CLASS B CLASS A CLASS B
D.CLASS A CLASS B CLASS B CLASS B
第9题:
1. public class Target { 2. private int i = 0; 3. public int addOne() { 4. return ++i; 5. } 6. } And: 1. public class Client { 2. public static void main(String[] args) { 3. System.out.println(new Target().addOne()); 4. } 5. } Which change can you make to Target without affecting Client?()
第10题:
Which two allow the class Thing to be instantiated using new Thing()?