Errors at lines 7 and 8 cause compilation to fail.
The program prints pairs of values for x and y that might not always be the same on the same line (for example, “x=2, y=1”).
The program prints pairs of values for x and y that are always the same on the same line (for example, “x=1, y=1”. In addition, each value appears twice (for example, “x=1, y=1” followed by “x=1, y=1”).
The program prints pairs of values for x and y that are always the same on the same line (for example, “x=1, y=1”. In addition, each value appears only for once (for example, “x=1, y=1” followed by “x=2, y=2”).
第1题:
有如下类定义:
class Point{
public:
Point(int xx=0,int yy=0):x(xx),y(yy) { }
private:
int x,y;
};
class Circle:public Point{
public:
Circle(int r):radius(r) { }
private:
int radius;
};
派生类Circle中数据成员的个数是( )。
A、3
B、1
C、5
D、2
答案:A
解析:本题考查默认构造函数和带参数的构造函数,题目中定义一个对象a(2)以及对象数组b[3],共执行3次构造函数,对象指针不调用构造函数。
第2题:
有以下程序: #include<iostream> using namespace std; class A { private: int x; public: A(int a) { x=a; } friend class B; }; class B { public: void print(A a) { a.x--; cout<<a, x<<end1; } }; int main () { A a(10); B b; b.print (a) ; return 0; } 程序执行后的输出结果是( )。
A.9
B.10
C.11
D.12
第3题:
下列哪个方法可用于创建一个可运行的类? ( )
A.public class X implements Runable {public void run(){...,.,}}
B.public class X implements Thread {public void run(){......}}
C.public class X implements Thread {public int run(){……}}
D.public class X implements Runable {protected void run(){.....}}
第4题:
若有以下程序: #include<iostream> using namespace std; class data { public: int x; data(int x) { data::x=x; } class A private: data dl; public: A(int x): dl(x){ } void dispaO cout<<dl.x<<","; } }; class B: public A { private: data d2; public: B(int x):A(x-1),d2(x){ } void dispb() { cout<<d2.x<<endl; } }; class C: public B { public: C(int x):B(x-1){ } void disp0 { dispa(); dispb(); } }; int main() { C obj(5); obj.disp(); return 0; } 程序执行后的输出结果是( )。
A.5,5
B.4,5
C.3,4
D.4,3
第5题:
有以下程序: #include<iostream> using namespace std; class sample { private: int x; public: sample(int A) { x=a; friend double square(sample s); }; double square(sample s) { return S.X*S.K; } int main() { sa
A.20
B.30
C.900
D.400
第6题:
有如下程序: #include<iostream> using namespace std; class Base{ public: Base(int x=0){cout<<x;} }; class Derived:public Base{ public: Derived(int x=0){cout<<x;} private: Base val; }; int main( ){ Derived d(1); return 0; } 程序的输出结果是
A.0
B.1
C.01
D.001
第7题:
interface A{
int x = 0;
}
class B{
int x =1;
}
class C extends B implements A {
public void pX(){
System.out.println(x);
}
public static void main(String[] args) {
new C().pX();
}
}
错误。在编译时会发生错误(错误描述不同的JVM 有不同的信息,意思就是未明确的
x 调用,两个x 都匹配(就象在同时import java.util 和java.sql 两个包时直接声明Date 一样)。
对于父类的变量,可以用super.x 来明确,而接口的属性默认隐含为 public static final.所以可
以通过A.x 来明确。
第8题:
下列类的定义中,有( ) 处语法错误。 class Base { public: Base(){} Base(int i) { data=i; } private: int data; }; class Derive: public Base { public: Derive(): Base(O) { } Derive(int x) { d=x; } void setvalue(int i) { data=i; } private: d; };
A.1
B.2
C.3
D.4
第9题:
有以下程序: #include<iostream> using namespace std; #definePl 3.14 Class Point {private: int x,y; public: Point(int a,intB) {X=a; y:b;} int getx() <return x;} int gety() {return y;}}; class Circle:public Point {pri
A.314
B.157
C.78.5
D.153.86
第10题:
若有以下程序: #include <iostream> using namespace std; class data { public: int x; data (int x) { data: :x=x; } }; class A { private: data d1; public: A(int x) : d1 (x) { } void dispa() { cout<<d1, x<<", "; } }; class B: public A { private: data d2; public: B(int x) : A(x-1),d2(x) {} void dispb() { cout<<d2.x<<end1; } }; class C : public B { public: C(int x) : B(x-1){} void disp () { dispa ( ); dispb (); } }; int main ( ) { C obj (5); obj.disp(); return 0; } 程序执行后的输出结果是( )。
A.5,5
B.4,5
C.3,4
D.4,3