11. java methods
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This document discusses Java methods. Some key points covered include: - Methods allow grouping of code to perform operations and are called by name. They can return values. - Advantages of methods include being time savers, allowing code repetition without retyping, and enabling modular programming. - The syntax for defining a method includes access modifiers, return type, name, and parameters. - Methods can be invoked from another method, as shown in an example finding the minimum of two numbers.
![Invoking a Method
public static void main(String[] args) {
int a = 11;
int b = 6;
int c = minFunction(a, b);
System.out.println("Minimum Value = " + c);
}](https://image.slidesharecdn.com/11-200223190355/85/11-java-methods-7-320.jpg)
![The void
Keyword
public static void main(String[]
args) {
printGrade(55);
printGrade(85);
}
public static void printGrade(double marks) {
if (marks >= 90) {
System.out.println("A+");
}else if (marks >= 80) {
System.out.println("A");
}else if (marks >= 70) {
System.out.println("B+");
}else if (marks >= 60) {
System.out.println("B");
}else if (marks >= 50) {
System.out.println("S");
}else {
System.out.println("F");
}
}](https://image.slidesharecdn.com/11-200223190355/85/11-java-methods-8-320.jpg)
11. java methods
- 1. Java Methods Dr. M H B Ariyaratne https://goo.gl/T7qtAS
- 2. What are Methods? â A set of code / Collection of Statements â Group together to perform an operation â Referred to by name â Called / Invoked by utilizing the method's name â Like a subprogram that acts on data and often returns a value â When method name is encountered in a program, the execution of the program branches to the body of that method. When the method is finished, execution returns to the area of the program code from which it was called, and the program continues on to the next line of code.
- 4. Advantages Time savers Allow for the repetition of sections of code without retyping the code Saved and utilized again and again in newly developed programs Allows several programmers to work independently on separate concepts which can be assembled at a later stage
- 5. Syntax public static int methodName(int a, int b) { // body } â public static â modifier â int â return type â methodName â name of the method â int a, int b â list of parameters
- 6. Example /** the snippet returns the minimum between two numbers */ public static int minFunction(int n1, int n2) { int min; if (n1 > n2) min = n2; else min = n1; return min; }
- 7. Invoking a Method public static void main(String[] args) { int a = 11; int b = 6; int c = minFunction(a, b); System.out.println("Minimum Value = " + c); }
- 8. The void Keyword public static void main(String[] args) { printGrade(55); printGrade(85); } public static void printGrade(double marks) { if (marks >= 90) { System.out.println("A+"); }else if (marks >= 80) { System.out.println("A"); }else if (marks >= 70) { System.out.println("B+"); }else if (marks >= 60) { System.out.println("B"); }else if (marks >= 50) { System.out.println("S"); }else { System.out.println("F"); } }
- 9. Method Overloading A class has two or more methods by the same name but different parameters It is different from overriding. In overriding, a method has the same method name, type, number of parameters, etc.
- 10. The Constructors â Initializes an object when it is created â Has the same name as its class â Syntactically similar to a method â Have no explicit return type. â Use to give initial values to the instance variables defined by the class, or to perform any other startup procedures required to create a fully formed object. â All classes have constructors, whether you define one or not, because Java automatically provides a default constructor that initializes all member variables to zero. However, once you define your own constructor, the default constructor is no longer used.
- 11. Parameterized Constructor A constructor that accepts one or more parameters. Parameters are added to a constructor in the same way that they are added to a method, just declare them inside the parentheses after the constructor's name.
- 12. This keyword this is a keyword in Java which is used as a reference to the object of the current class, with in an instance method or a constructor. Using this you can refer the members of a class such as constructors, variables and methods.
- 13. Thank you