下列程序中注释的哪个代码(1、2、3、4)是错误的?
Abstract class Takecare {
protected void speakHello() {} //1
public abstract static void cry(); //2
static int f(){ return 0 ;} //3
abstract float g(); //4
}
选项:
A:
1
B:
2
C:
3
D:
4
Abstract class Takecare {
protected void speakHello() {} //1
public abstract static void cry(); //2
static int f(){ return 0 ;} //3
abstract float g(); //4
}
1
2
3
4
以下文字与答案无关
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abstract class A {
abstract float getFloat (); //1
void f() //2
{ }
}
public class B extends A {
private float m = 1.0f; //3
private float getFloat () //4
{ return m;
}
}
选项: A:1
B:2
C:3
D:4
for (int i=0;i<list.length;i++)
System.out.print(listi]+" ");
System.out.println();
}
public static void main(String] args){
int] list1={0,1,2,3};
int] list2=new intlist1.length];
list2=list1;
PrintLst("数组1",list1);
PrintLst("数组2",list2);
list12]=list12]+10;
PrintLst("修改数组1后,数组2为",list2);
}}
">8.阅读下列程序,并给出程序运行的结果。public class CopyArray{
public static void PrintLst(String s,int] list){
System.out.print(s+":");
for (int i=0;i<list.length;i++)
System.out.print(listi]+" ");
System.out.println();
}
public static void main(String] args){
int] list1={0,1,2,3};
int] list2=new intlist1.length];
list2=list1;
PrintLst("数组1",list1);
PrintLst("数组2",list2);
list12]=list12]+10;
PrintLst("修改数组1后,数组2为",list2);
}}
for (int i=0;i<list.length;i++)
System.out.print(listi]+" ");
System.out.println();
}
public static void main(String] args){
int] list1={0,1,2,3};
int] list2=new intlist1.length];
list2=list1;
PrintLst("数组1",list1);
PrintLst("数组2",list2);
list12]=list12]+10;
PrintLst("修改数组1后,数组2为",list2);
}}
">9.阅读下列程序,并给出程序运行的结果。Public class CopyArray{
public static void PrintLst(String s,int] list){
System.out.print(s+":");
for (int i=0;i<list.length;i++)
System.out.print(listi]+" ");
System.out.println();
}
public static void main(String] args){
int] list1={0,1,2,3};
int] list2=new intlist1.length];
list2=list1;
PrintLst("数组1",list1);
PrintLst("数组2",list2);
list12]=list12]+10;
PrintLst("修改数组1后,数组2为",list2);
}}
byte ] a="abcd".getBytes();
try{ FileOutputStream out=new FileOutputStream(f);
out.write(a);
out.close();
FileInputStream in=new FileInputStream(f);
byte ] tom= new byte3];
int m = in.read(tom,0,3);
System.out.println(m); //【代码1】
String s=new String(tom,0,3);
System.out.println(s); //【代码2】
m = in.read(tom,0,3);
System.out.println(m); //【代码3】
s=new String(tom,0,3);
System.out.println(s); //【代码4】
}
catch(IOException e) {}
}
}
">12.上机调试题:请说出E类中标注的【代码1】~【代码4】的输出结果。
import java.io.*;
public class E {
public static void main(String args]) {
int n=-1;
File f =new File("hello.txt");
byte ] a="abcd".getBytes();
try{ FileOutputStream out=new FileOutputStream(f);
out.write(a);
out.close();
FileInputStream in=new FileInputStream(f);
byte ] tom= new byte3];
int m = in.read(tom,0,3);
System.out.println(m); //【代码1】
String s=new String(tom,0,3);
System.out.println(s); //【代码2】
m = in.read(tom,0,3);
System.out.println(m); //【代码3】
s=new String(tom,0,3);
System.out.println(s); //【代码4】
}
catch(IOException e) {}
}
}
public void methodTwo(int i){}
C:public static void methodTree(int i, int j){}
D:blic static void methodFour(int i){}
">13.以下哪个方法不可以加入类 Son? ( )
class Father{
public void methodOne(int i){}
public void methodTwo(int i){}
public static void methodTree(int i){}
public static void methodFour(int i){}
}
class Son extends Father{…}
选项: A:public static void methodOne(int i){}
B:public void methodTwo(int i){}
C:public static void methodTree(int i, int j){}
D:blic static void methodFour(int i){}
Byte]a= "abcd" . getBytes();
Try{ FileOutputStream out = new FileOutputStream(f);
Out.write(a);
Out.close();
FileInputStream in = new FileInputStream(f);
Byte] tom= new byte 3];
Int m= in. read(tom, 0,3);
System. out. println(m);//【代码1】
String s = new String(tom, 0, 3);
System. out. println(s); //代码2】
M= in.read(tom, 0, 3);
System. out. println(m);//代码3】
S = new String( tom, 0,3);
System. out. println(s);//【代码4】
Catch( IOException e){}
}
}
">15.请说出E类中标注的【代码1】~【代码4】的输出结果。Import java.io. *;
Public class E{
Public static void main(String args ]){
Int n= - 1;
File f = new File( " hello.txt");
Byte]a= "abcd" . getBytes();
Try{ FileOutputStream out = new FileOutputStream(f);
Out.write(a);
Out.close();
FileInputStream in = new FileInputStream(f);
Byte] tom= new byte 3];
Int m= in. read(tom, 0,3);
System. out. println(m);//【代码1】
String s = new String(tom, 0, 3);
System. out. println(s); //代码2】
M= in.read(tom, 0, 3);
System. out. println(m);//代码3】
S = new String( tom, 0,3);
System. out. println(s);//【代码4】
Catch( IOException e){}
}
}
out.write(a);
out.close();
FileInputStream in = new FileInputStream(f);
byte ] tom = new byte3];
int m = in.read(tom,0,3);
System.out.println(m); //代码1] (3)
String s = new String(tom,0,3);
System.out,println(s): //代码2](abc)
m= in.read(tom,0,3);
System.out.println(m) //代码3] (1)
s =new String(tom,0,3)
System.out.println(s): //代码4] (abc)
catch(IOException e)(]
">16.请说出 E类中标注的代码 1]一代码4]的输出结果import java.io.;public class E(public static void main(String args ]) (intn=-1;File f = new File("hello.txt");byte] a= "abcd".getBytes();try| FileOutputStream out = new FileOutputStream(f);
out.write(a);
out.close();
FileInputStream in = new FileInputStream(f);
byte ] tom = new byte3];
int m = in.read(tom,0,3);
System.out.println(m); //代码1] (3)
String s = new String(tom,0,3);
System.out,println(s): //代码2](abc)
m= in.read(tom,0,3);
System.out.println(m) //代码3] (1)
s =new String(tom,0,3)
System.out.println(s): //代码4] (abc)
catch(IOException e)(]
}
}
">18.(4)interface Com {
int add(int a, int b);
public static int get(int n){
return n;
}
public default int see(int n){
return n;
}
public default int look(int n){
return n;
}
}
class A implements Com{
public int add(int a, int b){
return a+b;
}
public int see(int n){
return n+1;
}
}
public class E {
public static void main(String args]){
A a = new A();
int m = a.add(12,6);
int n =Com.get(12);
int t = a.see(6);
int q = a.look(6);
System.out.printf("%d:%d:%d:%d",m,n,t,q);
}
}
}
});
}
public void show(Car c){
c.run();
c.show();
}}
abstract class Car{
public void run(){
System.out.println("car run");
}
public void show(){
System.out.println(getClass().getName());
}}
">19.请写出以下程序运行结果:package test;
public class Test {
public static void main(String] args) {
Test t = new Test();
t.show(new Car(){
public void run(){
System.out.println("test run");
}
});
}
public void show(Car c){
c.run();
c.show();
}}
abstract class Car{
public void run(){
System.out.println("car run");
}
public void show(){
System.out.println(getClass().getName());
}}
S1=set(1,2,2,3,3,3,4])
S2={1,2,5,6,4}
Print(s1&s2-s1.intersection(s2))
选项: A:{1,2, 4}
B:set()
C:1,2,2,3,3,3,4]
D:{1,2,5,6,4}
}
}
选项: A:错误:方法参数与变量不匹配
B:20 and 40
C:10 and 40
D:10 and 20
">21.以下代码的输出结果为( )。public class Pass{
static int j = 20;
public void amethod(int x){
x = x*2;
j = j*2;
}
public static void main(String args]){
int i = 10;
Pass p = new Pass();
p.amethod(i);
System.out.println(i+" and "+j);
}
}
选项: A:错误:方法参数与变量不匹配
B:20 and 40
C:10 and 40
D:10 and 20