methods intro-1.0
Post on 22-Jan-2015
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DESCRIPTION
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- 1. Introduction Methods
2. What is aMethod ?
- Amethodis a kind of building block that solves a small problem
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- A piece of code that has a name and can be called from the other code
- Methods allow programmers to construct large programs from simple pieces
- Methods are also known asfunctions ,procedures , andsubroutines
3. Why Use Methods?
- More manageable programming
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- Better organization of the program
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- Easy to read programs
- Avoid repeating code
- Code reusability
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- Using existing methods several times
4. Declaring andCreatingMethods 5. Declaring andCreatingMethods
- Each method has aname
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- It is used to call the method
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- Describes its purpose
publicstatic voidprintLogo () { System.out.println("FunSoft Corp."); System.out.println ("www.funsoft.bg"); } 6. Declaring andCreatingMethods (2)
- Methods declaredpubliccan be called by any other classes
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- This will be discussed later in details
- Methods declaredstaticcan be called by any other method (static or not)
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- This will also be discussed later
- The keywordvoidmeans that the method does not return any result
public s tatic void p rintLogo( ){ System.out.println("FunSoft Corp."); System.out.println ("www.funsoft.bg"); } 7. Declaring andCreatingMethods (3)
- Each method has abody
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- It contains the programming code
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- Surrounded by{and}
publicstatic void printLogo() { System.out.println("FunSoft Corp."); System.out.println("www.funsoft.bg"); } 8. Using Parameters Defining and Using Method Parameters 9. MethodParameters
- To pass information to a method, you can useparameters
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- You can pass zero or several values
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- You can pass values of different types
- Use parameters to change the way the method works every time you call it
10. Defining and UsingMethod Parameters
- Methods behavior depends on its parameters
- Parameters can be of any type
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- int ,double ,String , etc.
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- arrays ( int[] ,double[] , etc.)
public static void printSign( int number ) { if ( number> 0) System.out.println("Positive"); else if ( number< 0) System.out.println("Negative"); else System.out.println("Zero"); } 11. Returning Values From Methods 12. Returning Values From Methods
- A method canreturna value to its caller
- Returned value:
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- Can be assigned to a variable:
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- Can be used in expressions:
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- Can be passed to another method:
String message = input.nextLine(); // input.nextLine() returns a string float price =g etPrice ()* quantity * 1.20; System.out.println( input.nextLine() ) ; 13. Creating a Method That Returns a Value
- Instead ofvoid , specify the type of data you want to return
- Methods can return any type of data ( int ,String , array, etc.)
- voidmethods do not return anything
- Usereturnkeyword to return a result
public staticintmultiply(int number1, int number2) { returnnumber1 * number2; } 14. returnStatement
- returnstatement:
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- Terminatesmethods execution
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- Returns the given expression to the caller
- To terminatevoidmethod, simply writereturn;
- You can use return several times in a method
15. Questions ? Methods Introduction
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