超星 - 第四章面向对象（上）2 对象的创建与使用练习题 - 查题吧

单选题

下面哪个类的声明是正确的？

A. public void HH {...}
B. public class Move() {...}
C. public class void number {...}
D. public class Car {...}

单选题

假设已声明了一个类A的两个对象a1,a2，为了初始化a1和a2，下面语句正确的是：

A. a1,a2=new A();
B. a1=new ();a2=new();
C. a1=A() a2=A();
D. a1=new A();a2=new A();

单选题

如果编写一个main()方法调用HelloAccp类的show()方法，其运行结果是（）。public class HelloAccp{int a=100,b=50;public void avg(){float c=(a+b)/2;}public void show(){System.out.println("平均值为：“ + c);}}

A. 存在错误，提示：无法解析c
B. 平均值为：75
C. 平均值为：75.0
D. 存在错误，提示：无法将数据类型int转换为float

单选题

下列程序段的运行结果为______________。class Q1{public static void main（String args[ ]）{double d=10;Dec dec=new Dec( );dec.decrement(d);System.out.println(d);}}class Dec{public void decrement(double decMe){decMe = decMe - 5;}}

A. 10.0
B. 10
C. 5
D. 5.0

单选题

有类Person定义如下：public class Person {String name ;int age ;void show() {System.out.println("Hi,I'm "+name+",I'm " +age+" years old.");}}以下操作的结果是：Person p = new Person();System.out.print(p.name+" "+p.age+" ");p.name = "Alice";p.age = 12;System.out.println(p.name+" "+p.age+" ");

A. null 0 Alice 12
B. Alice 12 Alice 12
C. null 0 null 0
D. 都不对

单选题

有类Person定义如下：public class Person {String name = "Peter";int age = 10 ;void sayHi() {System.out.println("Hi,I'm "+name+",I'm " +age+" years old.");}}以下操作的结果是：Person p = new Person();System.out.print(p.name+" "+p.age+" ");p.name = "Alice";p.age = 12;System.out.println(p.name+" "+p.age+" ");

A. null 0 Alice 12
B. Peter10 Alice 12
C. Peter10Peter10
D. 都不对

单选题

有类Person定义如下：public class Person {String name = "Peter";int age = 10 ;void sayHi() {System.out.println("Hi,I'm "+name+",I'm " +age+" years old.");}}以下操作的结果是：Person p = new Person();Person p1 = p;p1.name = "Alice";p1.age = 12;System.out.print(p.name+" "+p.age+" ");System.out.println(p1.name+" "+p1.age+" ");

A. null 0 Alice 12
B. Peter 10 Alice 12
C. Alice 12 Alice 12
D. Peter 10 Peter 10

单选题

有类Person定义如下：public class Person {String name = "Peter";int age = 10 ;void sayHi() {System.out.println("Hi,I'm "+name+",I'm " +age+" years old.");}}以下操作的结果是：Person p = new Person();Person p1 = new Person();p1.name = "Alice";p1.age = 12;System.out.print(p.name+" "+p.age+" ");System.out.println(p1.name+" "+p1.age+" ");

A. null 0 Alice 12
B. Peter 10 Alice 12
C. Alice 12 Alice 12
D. Peter 10 Peter 10

单选题

有类Person定义如下：public class Person {String name;int age ;void show() {System.out.print (name+" " +age+" ");}}以下操作的结果是：Person p = new Person();p.show();p = new Person();p.name = "Alice";p.age = 12;p.show();

A. null 0 null 0
B. null 0 Alice 12
C. Alice 12 Alice 12
D. Alice 12 null 0

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