Introdução aos Objectos/Exercício 01: Gato simples: Difference between revisions

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Line 24: Line 24:
* The cat's name.
* The cat's name.
*/
*/
private String _name;
private String name;


/**
/**
* The cat's age.
* The cat's age.
*/
*/
private int _age;
private int age;


/**
/**
* The cat's weight.
* The cat's weight.
*/
*/
private double _weight;
private double weight;


/**
/**
Line 44: Line 44:
*/
*/
public Cat(String name, int age, double weight) {
public Cat(String name, int age, double weight) {
_name = name;
this.name = name;
_age = age;
this.age = age;
_weight = weight;
this.weight = weight;
}
}


/**
/**
* @return the _name
* @return the name
*/
*/
public String getName() {
public String getName() {
return _name;
return this.name;
}
}


Line 59: Line 59:
* @param name the name to set
* @param name the name to set
*/
*/
public void set_name(String name) {
public void setName(String name) {
_name = name;
this.name = name;
}
}


Line 67: Line 67:
*/
*/
public int getAge() {
public int getAge() {
return _age;
return this.age;
}
}


Line 73: Line 73:
* @param age the age to set
* @param age the age to set
*/
*/
public void set_age(int age) {
public void setAge(int age) {
_age = age;
this.age = age;
}
}


Line 81: Line 81:
*/
*/
public double getWeight() {
public double getWeight() {
return _weight;
return this.weight;
}
}


Line 87: Line 87:
* @param weight the weight to set
* @param weight the weight to set
*/
*/
public void set_weight(double weight) {
public void setWeight(double weight) {
_weight = weight;
this.weight = weight;
}
}


Line 98: Line 98:
if (o instanceof Cat) {
if (o instanceof Cat) {
Cat cat = (Cat) o;
Cat cat = (Cat) o;
return _name.equals(cat.getName()) && _age == cat.getAge() && _weight == cat.getWeight();
return this.name.equals(cat.name) && this.age == cat.age && this.weight == cat.weight;
}
}
return false;
return false;
Line 109: Line 109:
@SuppressWarnings("nls")
@SuppressWarnings("nls")
public String toString() {
public String toString() {
return _name + " (cat) (" + _age + ":" + _weight + ")";
return this.name + " (cat) (" + this.age + ":" + this.weight + ")";
}
}
}
}

Revision as of 16:38, 23 October 2013

Problema

Modele e implemente uma classe que represente uma versão muito simples do conceito Gato.

Um Gato tem como características o nome, a idade e o peso.

Implemente o método de comparação (equals), por forma a considerar que dois gatos são iguais se as suas características forem iguais.

Implemente o método de apresentação (toString), por forma a produzir uma cadeia de caracteres onde seja apresentado o nome, a idade e o peso do gato.

Implemente métodos de acesso às variáveis internas do gato.

Implemente um programa ("main") que ilustre a utilização dos métodos anteriores.

Solução

Class "Cat"

<java5> public class Cat {

/** * The cat's name. */ private String name;

/** * The cat's age. */ private int age;

/** * The cat's weight. */ private double weight;

/** * Fully specify the cat's initial state. * * @param name * @param age * @param weight */ public Cat(String name, int age, double weight) { this.name = name; this.age = age; this.weight = weight; }

/** * @return the name */ public String getName() { return this.name; }

/** * @param name the name to set */ public void setName(String name) { this.name = name; }

/** * @return the age */ public int getAge() { return this.age; }

/** * @param age the age to set */ public void setAge(int age) { this.age = age; }

/** * @return the weight */ public double getWeight() { return this.weight; }

/** * @param weight the weight to set */ public void setWeight(double weight) { this.weight = weight; }

/** * @see java.lang.Object#equals(java.lang.Object) */ @Override public boolean equals(Object o) { if (o instanceof Cat) { Cat cat = (Cat) o; return this.name.equals(cat.name) && this.age == cat.age && this.weight == cat.weight; } return false; }

/** * @see java.lang.Object#toString() */ @Override @SuppressWarnings("nls") public String toString() { return this.name + " (cat) (" + this.age + ":" + this.weight + ")"; } } </java5>

Test application (main)

<java5> public class Application { public static void main(String[] args) { Cat cat = new Cat("Tareco", 12, 3.141); System.out.println(cat.equals(new Cat("Tareco", 12, 3.141))); // prints "true" System.out.println(cat.equals(new Cat("Pantufa", 1, 2.718))); // prints "false" System.out.println(cat); } } </java5>

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