variables must have a type
variables must have a name
1 int count 2 // type int 3 //count name
无法用小杯子装完大杯子的水,会损失某些信息,也就是溢位。
1 //myDog为Dog的引用变量 2 //Dog引用变量就像是Dog的遥控器,遥控器上有个按钮是bark; 3 Dog mydog = new Dog(); 4 myDog.bark();
[db:关键字]