Question

Give the method header for each of the following methods: a) Method hypotenuse, which takes two double-precision, floating-point arguments side1 and side2 and returns a double-precision, floating-point result. b) Method smallest, which takes three integers \(x, y\) and \(z\) and returns an integer. c) Method instructions, which does not take any arguments and does not return a value. \([\)Note: Such methods are commonly used to display instructions to a user. d) Method intToFloat, which takes integer argument number and returns a float.

Short answer

a) public double hypotenuse(double side1, double side2)b) public int smallest(int x, int y, int z)c) public void instructions()d) public float intToFloat(int number)

Step-by-step solution

Identify Return Type and Parameters for hypotenuse

Method hypotenuse should return a double and take two doubles as parameters - these represent the sides of a right triangle.

Identify Return Type and Parameters for smallest

Method smallest should return an integer and take three integers as parameters to compare and find the smallest.

Identify Return Type and Parameters for instructions

Method instructions does not take any parameters and does not return any value, so it should be void.

Identify Return Type and Parameters for intToFloat

Method intToFloat should return a float and take one integer as a parameter to be converted.

Key concepts

Method Overloading

Method overloading is a feature in Java that allows a class to have more than one method with the same name, provided that the number and/or type of parameters are different. It is a way of implementing polymorphism at the compile-time. This enables us to create methods that behave differently depending on the arguments passed to them. For example, our textbook exercise introduces various methods with unique purpose and parameters. If we were to add another hypotenuse method that takes, say, integers instead of doubles, we would be overloading it.

Overloading is particularly useful because it makes the code more readable and reusable, and it allows us to perform different functions without needing to remember multiple method names. Java distinguishes the different methods by their method signatures. A method signature includes the method name and the parameter list. The return type is not considered part of the method signature for overloading purposes.

However, there are few rules for method overloading: methods must differ in either the number of parameters or the type of parameters. If only the return type is different, Java does not consider it as method overloading. For instance, our smallest method cannot be overloaded with another smallest method that only differs in that it returns a double. The parameters must be distinct.

Parameter Passing in Java

Understanding how arguments are passed to methods in Java is key to working effectively with functions. When a variable is passed into a method, Java uses 'pass by value', which means that a copy of the variable's value is made and passed into the method.

This is especially important with our Java primitive types (like double and int), as it ensures that the original variable's value cannot be altered. For instance, in our exercise, when we pass values into the hypotenuse or smallest methods, the original values of side1, side2, x, y, and z remain unchanged outside the method.

If we pass objects into methods, Java still uses pass by value, but since the value is the reference to the object, changes through this reference will affect the original object. However, the in-class exercises usually stick to primitive types, which streamlines the learning process by mitigating complexity.

Java Primitive Data Types

Primitive data types in Java are the basic types of data built-in to the language. There are eight primitive data types: byte, short, int, long, float, double, char, and boolean. They store simple values and are not objects. In the context of our exercise:

• double: The hypotenuse method uses this data type for both the parameters and the return type, as it can handle decimal numbers with high precision.
• int: The smallest method uses integers to find the smallest of three given values, demonstrating the use of this type for whole numbers.
• float: The intToFloat method returns a float, which is a single-precision, floating-point number less precise than double, but still capable of holding decimals.

Understanding these data types is critical as they set the foundation for manipulating data in Java programs. Choosing the proper data type can affect the accuracy of data calculations and memory usage.