publicclassPet{publicvoidspeak(){System.out.print(Pet”);}}publicclassCatextendsPet{publicvoidspeak(){System.out.print(Cat”);}}publicclassDogextendsPet{publicvoidspeak(){System.out.print(Dog”);}}执行代码Pet[]p={newCat(),newDog(),newPet()};for(inti=0;i〈p.length;i++)p[i].speak();后输出的内容是哪项?()
A.PetPetPet
B.CatCatCat
C.CatDogPet
D.CatDogDog
第1题:
A.Petp=(Pet)c运行错误
B.Petp=(Pet)c编译错误
C.Petp=(Pet)c止常执行
D.以上都不对
第2题:
下列程序片段中,能通过编译的是( )。
A.public abstract class Animal{ public void speak;}
B.public abstract class Animal{ public void speak{);}
C.public class Animal{ pubilc abstract void speak;}
D.public abstract class Animal{ pubile abstract void speak{};}
第3题:
下列程序片段中,能通过编译的是( )。
A.public abstract class Animal{ public void speak;}
B.public abstract class Animal{ public void speak{);}
C.public class Animal{ pubilc abstract void speak;}
D.public abstract class Animal{ pubile abstract void speak{};}
第4题:
下列程序片段中,能通过编译的是( )。
A.public abstract class Animal{public void speak( );}
B.public abstract class Animal{public void speak( ){};}
C.public class Animal{pubilc abstract void speak( );}
D.public abstract class Animal{pubile abstract void speak( ){};}
第5题:
下列程序片段中,能通过编译的是( )。
A.public abstract class Animal{ public void speak( );}
B.public abstract class Animal{ public void speak( ){};}
C.public class Animal{ pubilc abstract void speak( );}
D.public abstract class Animal{ pubilc abstract void speak( ){};}