发布时间 : 星期一 文章JAVA程序设计-答案更新完毕开始阅读d3c2a41d10a6f524ccbf852b
}
}
运行结果是:( ) 6 1 12 12
7.分析下面的程序,写出运行结果。 class Exercises6_3 { class Dog { private String name; private int age; public int step;
Dog(String s, int a) { name = s; age = a; step = 0;
}
public void run(Dog fast) { fast.step++;
}
}
public static void main(String args[]) { Exercises6_3 a = new Exercises6_3(); Dog d = a.new Dog(\ d.step = 29; d.run(d);
System.out.println(\
}
}
运行结果是:( ) 30
8.分析下面的程序,写出运行结果。
class Aclass { void go() { System.out.println(\public class Bclass extends Aclass {
void go() { System.out.println(\
public static void main(String args[]) { Aclass a = new Aclass(); Aclass a1 = new Bclass(); a.go();
a1.go(); } }
运行结果是:( ) Aclass Bclass
9.计算调用下列方法的结果。
Math.sqrt(4); // 2.0 Math.pow(4, 3); // 64.0 Math.max(2, Math.min(3, 4)); // 3
10.下列程序中构造了一个set并且调用其方法add(),输出结果是( 2 )。 import java.util.*;
public class T1_2 {
public int hashCode() { }
}
public boolean equals(Object b) { }
return true; return 1;
public static void main(String args[]) { Set set = new HashSet(); }
set.add(new T1_2());
set.add(new String(\set.add(new T1_2());
System.out.println(set.size());
五、改错题(每题20分,共6题)
1.找出下面代码的错误部分,说明错误类型及原因,并更正。
public int m1 (int number[20]){
}
number = new int[20];
for(int i=0;i number[i] = number[i-1] + number[i+1]; return number; 改正后程序: public int[] m1(int number[]) { // number = new int[20]; for (int i = 1; i < number.length - 1; i++) number[i] = number[i - 1] + number[i + 1]; return number; } 2.找出下面代码的错误部分,说明错误类型及原因,并更正。 (1) int x = 1; while (x <= 10); (2) switch (n) { case 1: system.out.println(\case 2: system.out.println(\break; { i++; } 改正后程序: int x = 1, i = 0; while (x <= 10) { } i++; } 改正后程序: int n = 1; switch (n) { case 1: System.out.println(\); break; case 2: System.out.println(\); break; } 3.下面的程序中有若干个语法错误,找出后请改正。 public class MyMainClass{ public static void main( ) { TheOtherClass obj = new TheOtherClass(\ System.out.println(obj.name+' '+obj.gender+' '+obj.nationality); } System.out.println(\} public class TheOtherClass{ private String name,gender,nationality; public TheOtherClass(String name,String gender,String nationality){ this.name=name; this.gender=gender; } } 改正后程序: public class MyMainClass { y); System.out.println(\); } public static void main(String args[]) { TheOtherClass obj = new TheOtherClass(\, \, \); System.out.println(obj.name + ' ' + obj.gender + ' ' + obj.nationalit this.nationality=nationality; } class TheOtherClass { public String name, gender, nationality; public TheOtherClass(String name, String gender, String nationality) { this.name = name; this.gender = gender; this.nationality = nationality; } } 4.下面的程序中有若干个语法错误,找出后请改正。 public class Car{ } public static void setCarName(){ carName=\} public static void setMileage(){ mileage=180; } } 改正后程序: public abstract class Car { private String carName; private String carName; public int mileage; private static final int TOP_SPEED=50; abstract void alert(); public static int getTopSpeed(){ return TOP_SPEED;