Object Initialization:
Constructors are special methods that initialize objects when they are created.
They have the same class name and have no return type.
Utility:
Constructors are used to provide initial values to instance variables or perform other initialization tasks.
Default Constructor:
If a class does not define a constructor, Java automatically provides a default constructor.
This default constructor initializes numeric variables to zero, references to null, and booleans to false.
Example:
The MyClass class has a constructor that initializes the instance variable x with the value 10.
// Um construtor simples. class MyClass { int x; // Construtor da classe MyClass MyClass() { x = 10; // Inicializa x com 10 } } class ConsDemo { public static void main(String args[]) { MyClass t1 = new MyClass(); // Cria uma instância de MyClass MyClass t2 = new MyClass(); // Cria outra instância de MyClass // Exibe os valores de x para ambas as instâncias System.out.println(t1.x " " t2.x); } }
Parameterized Constructors
Example:
The MyClass class has a parameterized constructor that accepts an integer i and initializes x to that value.
When creating objects, different values can be passed to initialize x with specific values.
These topics highlight the importance of constructors for the safe and correct initialization of objects, in addition to allowing the creation of instances with different initial states.
// Um construtor parametrizado. class MyClass { int x; // Construtor parametrizado da classe MyClass MyClass(int i) { x = i; // Inicializa x com o valor passado no parâmetro i } } class ParmConsDemo { public static void main(String args[]) { MyClass t1 = new MyClass(10); // Cria uma instância de MyClass com x = 10 MyClass t2 = new MyClass(88); // Cria outra instância de MyClass com x = 88 // Exibe os valores de x para ambas as instâncias System.out.println(t1.x " " t2.x); } }
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