Learning the Java Language (2) : Classes and Objects

Classes and Objects



Classes

class MyClass extends MySuperClass implements YourInterface {
    // fields
    public int cadence;
        
    // constructor
    public Bicycle(int startCadence, int startSpeed, int startGear) {
        gear = startGear;
        cadence = startCadence;
        speed = startSpeed;
    }
        
    // methods
    public void setCadence(int newValue) {
        cadence = newValue;
    }
}

//定義了MyClass類別，繼承了MySuperClass，並用了YourInterface的介面[?!]

//field為初始值設定，constrctor為類別主要的輸入及功能，method為類別提供的多種方法

1. 

public modifier—the field is accessible from all classes

private modifier—the field is accessible only within its own class

[variable names]

• the first letter of a class name should be capitalized, and [類別名的首字母應該大寫]
• the first (or only) word in a method name should be a verb. [method的首字母應該動詞]

2.

Java can distinguish between methods with different method signatures.

This means that methods within a class can have the same name

if they have different parameter lists

[只要輸入的參數不一樣，method名稱一樣沒關係(在同一class裡面)，JAVA分得出來]

[Overloading Methods] 

3.

在寫constructor時，建議書寫一個完全給予引數的constructor

跟一個完全沒有input的constructor，確保輸出都有數值

不可以寫兩個一樣input的constructor，會編譯錯誤