举一反三
- E类中System.out.println的输出结果是__________、________________。interface Com{int add(int a,int b);}abstract class A{abstract int add(int a,int b);}class B extends A implements Com{public int add(int a,int b){return a+b;}}public class E{public static void main(String args[ ]){B b=new B();Com com=b;System.out.println(com.add(12,6));A a=b;System.out.println(a.add(10,5));}}
- 阅读程序题(给出【代码】注释标注的代码的输出结果)interface Com {int add( int a, int b);}abstract class People {abstract int add( int a, int b);}class Student extends People implements Com{public int add(int a,int b) {return a + b;}}public class 习题5_阅读3 {public static void main(String args[ ]) {Student stu = new Student ();Com com = stu;int m = com.add(12,6);People p = stu;int n = p.add(12,8);System.out.printf("%d:%d",m,n); //【代码】}}
- 5.请说出E类中[代码1]，[代码2]的输出结果依次是______ ，______ 。 interface Com { int add(int a,int b); }abstract class A { abstract int add(int a,int b);int g(int a,int b) { return a+b; }}class B extends A implements Com{ public int add(int a,int b) { return a+b; } int g(int a,int b) { return a*b; }}public class E {public static void main(String args[]) { B b = new B(); Com com = b; System.out.println(com.add(10,5)); //[代码1] A a = b; System.out.println(a.g(10,5)); }} //[代码2]
- 程序填空：interface Com{ int M=200; int f(); } class ImpCom implements Com{ ___________________________; } A: public int f(){retrun 100+M;} B: int f() {return 100;} C: public double f(){return 2.6;} D: public abstract inf f();
- 阅读程序题(给出【代码】注释标注的代码的输出结果)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 习题5_阅读4{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); //【代码】 }}}
内容
- 0
下列选项中，（ ）代码替换源文件Com.java中的【代码】不会导致编译错误。public interface com{int M=200;int f();}class ImpCom implements Com{【代码】} A: public int f( ){return 100+M;} B: int f( ){return 100;} C: public double f( ){return 2.6;} D: public abstract int f( );
- 1
请写出下列程序的输出结果。class A{public int f(int x) {return x+1;}}class B extends A{public int f(int x){return x*x;}}public class E{public static void main(String args[]){A a=new B();int m=a.f(10);System. out. println(m) ;}}
- 2
将下列(A,B,C,D)哪个代码替换下列程序中的【代码】不会导致编译错误。(<br/>) A: public<br/>int f(){return 100+M;} B: int<br/>f(){return 100;} C: public<br/>double f(){return 2.6;}。 D: public<br/>abstract int f();<br/>interface Com {<br/>int M = 200;<br/>int f();}<br/>class ImpCom implements Com {<br/>【代码】}
- 3
public class test { public static void main(String args[]) { int m=0; for ( int k=0;k<2;k++) method(m++); System.out.println(m); } public static void method(int m) { System.out.print(m); } }
- 4
给出下列【代码】注释标注的代码的输出结果。abstract class A {abstract int get(int a,int b);}public class E {public static void main(String args[]) {A a=new A() {public int get(int a,int b){return a+b;}};int m = a.get(2,5);a=new A() {public int get(int a,int b){return a*b;}};int n = a.get(2,5);System.out.printf("%d:%d",m,n);//【代码】}}