201707 CSE110 Lecture 15
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This document contains lecture slides about classes and objects in Java from a CSE110 Principles of Programming course taught by Javier Gonzalez-Sanchez in the summer of 2017. The slides discuss static variables and methods, how non-static and static members can access each other, creating and calling methods, the object-oriented paradigm of creating objects to call methods on, and provide examples of method definitions and calls. Reference materials are listed on slide 14.
![Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 7
Object-Oriented Paradigm
public class Student {
String name;
int finalGrade;
public void sayHello(){
// print name
}
public void drawSomething(){
// draw
}
}
public class MyProgram {
public static void main(String [] arg) {
Student john = new Student();
john.name = "John Doe";
john.sayHello();
jane.name = "Jane Doe";
jane.sayHello();
}
}
john jane](https://image.slidesharecdn.com/cse110l15-objects-170708041811/85/201707-CSE110-Lecture-15-7-320.jpg)
201707 CSE110 Lecture 15
- 1. CSE110 Principles of Programming with Java Lecture 15: Classes and Objects Javier Gonzalez-Sanchez javiergs@asu.edu javiergs.engineering.asu.edu Office Hours: By appointment
- 3. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 3 static class static int variable1; public static void sayHelloAll(){ } int variable2; public void sayHello (){ }
- 4. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 4 static • Non-static methods can use static and non-static variables • static methods can only use static variables. • static variable = class variable • Non-static variable = instance/object variables/attributes.
- 5. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 5 static class static int variable1; public static void sayHelloAll(){ variable1 =0; variable2 =0; } int variable2; public void sayHello (){ variable1 =0; variable2 =0; }
- 6. Communication Call and Create Methods
- 7. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 7 Object-Oriented Paradigm public class Student { String name; int finalGrade; public void sayHello(){ // print name } public void drawSomething(){ // draw } } public class MyProgram { public static void main(String [] arg) { Student john = new Student(); john.name = "John Doe"; john.sayHello(); jane.name = "Jane Doe"; jane.sayHello(); } } john jane
- 8. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 8 Call Methods • john.sayHello(); • john.sayHello("in French"); • int x = john.giveMeANumber(); • int result = john.addThisNumbers(2,2);
- 9. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 9 Create Methods • public void sayHello() { } • public void sayHello(String language) {} • public int giveMeANumber(){} • Public int addThisNumbers(int x, int y) {}
- 10. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 10 Methods • public or private • static (optional) • type (void, int, double, String, etc.) • name • (parameters) • { body }
- 11. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 11 Example
- 12. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 12 Example
- 13. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 13 Example
- 14. Javier Gonzalez-Sanchez | CSE110 | Summer 2017 | 14 Reference Pages 201 - 207
- 15. CSE110 - Principles of Programming Javier Gonzalez-Sanchez javiergs@asu.edu Summer 2017 Disclaimer. These slides can only be used as study material for the class CSE110 at ASU. They cannot be distributed or used for another purpose.