2018年自考《Java语言程序设计》综合练习题四
四、写出下面程序的运行结果。
1．import java.io.*;
public class abc
{ public static void main(String args[ ])
{ AB s = new AB("Hello!","I love JAVA.");
System.out.println(s.toString( ));
}
}
class AB {
String s1;
String s2;
AB( String str1 , String str2 )
{ s1 = str1; s2 = str2; }
public String toString( )
{ return s1+s2;}
}
答：Hello! I love JAVA.
2．import java.io.* ;
public class abc
{
public static void main(String args[ ])
{ int i , s = 0 ;
int a[ ] = { 10 , 20 , 30 , 40 , 50 , 60 , 70 , 80 , 90 };
for ( i = 0 ; i < a.length ; i ++ )
if ( a[i]%3 = = 0 ) s += a[i] ;
System.out.println("s="+s);
}
}
答：s = 180
3． import java.io.* ;
public class abc
{
public static void main(String args[ ])
{ SubSubClass x = new SubSubClass(10 , 20 , 30);
x.show();
}
}
class SuperClass
{ int a,b;
SuperClass(int aa , int bb)
{ a=aa; b=bb; }
void show( )
{ System.out.println("a="+a+" b="+b); }
}
class SubClass extends SuperClass
{ int c;
SubClass(int aa,int bb,int cc)
{ super(aa,bb);
c=cc;
}
}
class SubSubClass extends SubClass
{ int a;
SubSubClass(int aa,int bb,int cc)
{ super(aa,bb,cc);
a=aa+bb+cc;
}
void show()
{ System.out.println("a="+a+" b="+b+" c="+c); }
}
答：a=60
b=20
c=30
4． import java.io.*;
public class abc
{
public static void main(String args[])
{
String s1 = "Hello!";
String s2 = new String("World!");
System.out.println(s1.concat(s2));
}
}
答：Hello! World!
5． import java.io.* ;
public class ABC
{
public static void main(String args[ ])
{ int i ;
int a[ ] = { 11,22,33,44,55,66,77,88,99 };
for ( i = 0 ; i <= a.length / 2 ; i ++ )
System.out.print( a[i]+a[a.length-i-1]+" ");
System.out.println( );
}
}
答：110 110 110 110 110
6． import java.io.*;
class Parent
{
void printMe()
{
System.out.println("parent");
}
}
class Child extends Parent
{
void printMe()
{
System.out.println("child");
}
void printAll()
{
super.printMe();
this.printMe();
printMe();
}
}
public class Class1
{
public static void main(String args[ ])
{
Child myC = new Child( );
myC.printAll( );
}
}
答：parent
child
child
