Labs

In these labs we will practice using equals and hashCode.

  1. The RGBColor class has three integer fields. Add an equals method to RGBColor so the tests shown in TestColor come out correctly based on the values of the three integer fields.

(Solution: RGBColor.java)

  1. In RGBColor, implement the hashCode method. Starting with a prime number like 17, multiply the prime number by itself and each of the three field values, adding the result back to the prime after each multiplication.

(Solution: RGBColor2.java)

  1. The Triangle class has two int fields, base and height. Write an equals method for it so the tests in TestTriangle come out correctly.

(Solution: Triangle.java)

  1. The ColorTriangle class extends Triangle, adding a field of type RGBColor. Give ColorTriangle an equals method that invokes Triangle's equals to check base and height, and also uses RGBColor's equals to compare the color field.

(Solution: ColorTriangle.java)

  1. In Triangle, comment out your equals method. In the Eclipse Source menu, use Generate hashCode() and equals() to see Eclipse's default implementations for these methods. Do the same with your ColorTriangle class.

(Solution: Triangle2.java, ColorTriangle2.java)

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