class Father{ int x; public Father(int x){ this.x=x; } public Father(){;} public int fun(){ int f=0; for (int i=1;i<=x;i++) f=f+i; return f; } public int fun(int x){ int f=1; for(int i=1;i<=x;i++) f=f*i; return f; } } class Son extends Father{ public Son(int a){ super(); } public int fun(){ int f=1; for(int i=1;i<=x;i++) f=f*i; return f; } } public class { public static void main(String[] args){ Father f1=new Father(5); Son s1=new Son(3); System.out.println(s1.fun()); System.out.println(f1.fun()); System.out.println(f1.fun(6)); s1=f1; System.out.println(s1.fun()); System.out.println(f1.fun()); System.out.println(f1.fun(6)); } }
Father.java文件名改为Pol_ex public class 后面的 类名 要和文件名一致
public class Pol_ex { public static void main(String[] args) { Father f1 = new Father(5); Father s1 = new Son(3); System.out.println(s1.fun()); System.out.println(f1.fun()); System.out.println(f1.fun(6)); s1 = f1; System.out.println(s1.fun()); System.out.println(f1.fun()); System.out.println(f1.fun(6)); } }Father s1 = new Son(3);
int x;
public Father(int x){
this.x=x;
}
public Father(){;}
public int fun(){
int f=0;
for (int i=1;i<=x;i++)
f=f+i;
return f;
}
public int fun(int x){
int f=1;
for(int i=1;i<=x;i++)
f=f*i;
return f;
}
}
class Son extends Father{
public Son(int a){
super();
}
public int fun(){
int f=1;
for(int i=1;i<=x;i++)
f=f*i;
return f;
}
}
public class {
public static void main(String[] args){
Father f1=new Father(5);
Son s1=new Son(3);
System.out.println(s1.fun());
System.out.println(f1.fun());
System.out.println(f1.fun(6));
s1=f1;
System.out.println(s1.fun());
System.out.println(f1.fun());
System.out.println(f1.fun(6));
}
}
public class 后面的 类名 要和文件名一致
public class Pol_ex {
public static void main(String[] args) {
Father f1 = new Father(5);
Father s1 = new Son(3);
System.out.println(s1.fun());
System.out.println(f1.fun());
System.out.println(f1.fun(6));
s1 = f1;
System.out.println(s1.fun());
System.out.println(f1.fun());
System.out.println(f1.fun(6));
}
}Father s1 = new Son(3);
但Java文件名必须与public的class同名