Java Basic (3) - toString(), constructor

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toString()

• Automatically called by Java when printing or concatenation is needed with your object

 

toString() the class file. e.g. Amy(1/5)

print in the main. Output : Amy(1/5)

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constructor

• used to instantiate (create an instance of) an object
• normally use it to initialize the instance variables
• use to do any kind of processing that needs to be done when the object is created
• no return type
• must have the exact same name as the class
• Java provides a default constructor that does not do anything except instantiating the object in case no constructor is defined in a class (disappears as soon as any constructor is defined in the class)

 

main. shows how to call the constructor

Two different constructors

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