Einführung in die objektorientierte Programmierung

Objekte

Person

class Person{
 String name;
 int alter;
 String strasse;
 
 static int anzahl;
 
 boolean equals(Person o){
 if (alter==o.alter) 
 return true;
 else return false;
 }
 
 public static void main(String[] args){
 
 Person p1 = new Person();
 
 p1.alter = 45;
 
 System.out.println(p1.alter);
 
 p1.anzahl= 1;
 
 System.out.println(p1.anzahl);
 
 Person p2 = new Person();
 
 p2.alter = 45;
 
 System.out.println(p2.alter);
 
 p2.anzahl= 2;
 
 System.out.println(p1.anzahl);
 
 if (p1.equals(p2)) {
 System.out.println("Objekte gleich");
 } // end of if
 else  System.out.println("Objekte ungleich");
 
 }
 
 }

Person 2

class Person2{
 String name;
 int alter;
 String strasse;
 
 public void set_name(String name){
 this.name = name;
 }
 
 public String get_name(){
 return name;
 }
 
 static int anzahl;
 
 public static void main(String[] args){
 
 Person2 p1 = new Person2();
 
 p1.set_name("Bernd");
 
 System.out.println("Name: " + p1.get_name() );
 
 Person2 p2= p1; 
 
 p1.set_name("Ulrike");
 
 System.out.println("Name: " + p2.get_name() );
 
 }
 
 }
 

Person 3

class Person3{
   String name;
   int alter;
   String strasse;
   static int anzahl=0;
   
   public void set_name(String name){
   this.name = name;
   }
   
   public String get_name(){
   return name;
   }
   
   Person3(String n, int alter, String str){
   name=n;
   this.alter = alter;
   strasse = str;
   anzahl++;
   } 
   
   Person3(){
   anzahl++;
   }
   
   public void ausgabe(){
   System.out.println(name);
   System.out.println(alter);
   System.out.println(strasse);
   System.out.println("Anzahl Personen: " + anzahl);
   }
   
   public static void main(String[] args){
   
   Person3 p1 = new Person3("Kurt",87,"Moorweide 6");
   
   p1.ausgabe();
   
   Person3 p2 = p1;
   
   for (int i=0; i<=100 ; i++ ) {
   
   } // end of for

 System.out.println(p1 + " " + p2);
   
   Stud s1 = new Stud("name",20, "str", "123456");
   
   }
   
   }

class Stud extends Person3{
  String matrikel;
  
  Stud(String n, int a, String str, String m){
    matrikel= m;
  }
  
}

Game of Life

public class GameOfLife {
 boolean[][] feld = { { false, false, false, false, false },
 { false, false, true, false, false },
 { false, false, true, false, false },
 { false, false, true, false, false },
 { false, false, false, false, false } };
 public static void main(String[] args) {
 GameOfLife myGame = new GameOfLife();
 for (int i = 0; i < 10; i++) {
 myGame.nextGeneration();
 myGame.print();
 System.out.println();
 }
 }
 void print() {
 for (int i = 0; i < feld.length; i++) {
 for (int j = 0; j < feld[i].length; j++) {
 if (feld[i][j] == true)
 System.out.print("o ");
 else
 System.out.print(". ");
 }
 System.out.println();
 }
 }
 void nextGeneration() {
 boolean[][] alt = new boolean[feld.length][feld[0].length];
 
 for (int i=0;i<feld.length ; i++) {
 for (int j=0;j< feld[0].length; j++ ) {
 alt[i][j] = feld[i][j];
 } // end of for
 } // end of for
 
 for (int i=0;i<feld.length ; i++) {
 for (int j=0;j< feld[0].length; j++ ) {
 if (i==0 || j==0 || i==feld.length-1 || j==feld[0].length-1) {
 feld[i][j]=false;
 } // end of if
 else{
 int anz=0;
 if (alt[i-1][j-1]) anz++;
 if (alt[i-1][j]) anz++;
 if (alt[i-1][j+1]) anz++;
 if (alt[i][j-1]) anz++;
 if (alt[i][j+1]) anz++;
 if (alt[i+1][j-1]) anz++;
 if (alt[i+1][j]) anz++;
 if (alt[i+1][j+1]) anz++;
 if (anz==3) feld[i][j]=true;
 if (anz<2 || anz>3) feld[i][j]=false; 
 }
 } // end of for
 } // end of for
 
 }
 }

Summe Gauss

public class Summierer {
 public static void main(String[] args) {
 Summierer summierer = new Summierer();
 int startWert = Integer.parseInt(args[0]);
 System.out.println("Ergebnis mit for-Schleife: "
 + summierer.forSumme(startWert));
 System.out.println("Ergebnis kleiner Gauss: "
 + summierer.kleinerGauss(startWert));
 System.out.println("Ergebnis rekursiv: "
 + summierer.rekursiveSumme(startWert));
 }
 int forSumme(int startWert) { 
 int summe=0; 
 for (int i=0; i<= startWert ; i++) {
 summe += i;
 } // end of for
 return summe;
 }
 int rekursiveSumme(int startWert) { 
 if (startWert==1) {
 return 1;
 } // end of if
 else if(startWert<1){
 return 0;
 } // end of if-else
 else {
 return startWert + rekursiveSumme(startWert-1);
 } // end of if-else
 
 }
 int kleinerGauss(int startWert) { 
 return (startWert*(startWert+1))/2;
 }
 }