Static Methods Jan 14 2019 About methods A method is a named group of declarations and statements You execute those declarations and statements by calling the method When you call the method you can give it parameters information such as numbers going into the method A method typically has a return value a single piece of information coming out of the method parameter parameter parameter Declarations and statements return value Why methods Methods help you break up a complex problem into simpler subproblems which you can solve separately Methods can use other methods but should not depend on the inner workings of those other methods just what they do not how they do it Methods allow you to give names to parts of your computation thus making your program more readable Readability is essential in good programming Proper choice of method names is important Verbs are usually best since methods do something If you have anything the least bit complicated to compute you should write and debug it in only one place This is an application of the DRY principle Don t Repeat Yourself Methods are very good for putting code in only one place Defining a static method A static method has the syntax static return type method name parameters method variables code Example static boolean isAdult int age int magicAge 21 return age magicAge Example static double average int a int b return a b 2 0 Returning a result from a method If a method is to return a result it must specify the type of the result static boolean isAdult You must use a return statement to exit the method with a result of the correct type return age magicAge Returning no result from a method The keyword void is used to indicate that a method doesn t return a value The return statement must not specify a value Example static void printAge String name int age System out println name is age years old return There are two ways to return from a void method Execute a return statement Reach the closing brace of the method Non static methods This slide set only talks about static methods Most methods in a Java program will not be static However before we can talk about what it means to be static we have to introduce classes and methods So more to come The End
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