Tugas Ku JAVA

banyak berlatih ya teman-2ku..
ingat Program Dibawah ini jangan dicopy,, kecuali jika kepepet...
jika terpaksa mengcopy tolong dipelajari lagi supaya lebih dipahami

1.....
/*---------------------------------------------------------------
Nama program : Manghitung Selisih Waktu
Deskripsi : menghitung Waktu dengan OOP
-----------------------------------------------------------------*/
import java.io.*;

class Waktu{
int jam ,menit,detik;

public Waktu(){
jam = 0;
menit = 0;
detik = 0;
}

public void inisialisasi(int jamMulai, int mntMulai, int dtkMulai){
System.out.println("Waktu Mulai");
jam = jamMulai ;
menit = mntMulai ;
detik = dtkMulai;
}

public void inputWaktu(){
System.out.println("Waktu Selesai");
String str;
System.out.print("Jam : ");
str = BacaKeyboard.bacaString();
jam = Integer.valueOf(str).intValue();

System.out.print("Menit : ");
str = BacaKeyboard.bacaString();
menit = Integer.valueOf(str).intValue();

System.out.print("Detik : ");
str = BacaKeyboard.bacaString();
detik = Integer.valueOf(str).intValue();
}

public void cetak (){

System.out.println( jam + ":" + menit + ":" + detik);

}

public void hitungWaktu (Waktu A, Waktu B){
System.out.println("LAMA");
if (B.detik <>
B.detik += 60;
B.menit --;
}
detik = B.detik - A.detik;


if (B.menit <>
B.menit += 60;
B.jam --;
}
menit = B.menit - A.menit;


if (B.jam <>
B.jam += 24;
}
jam = B.jam - A.jam;
}
}
public class Lama{
public static void main (String [] args) {
Waktu obj1 = new Waktu ();
obj1.inisialisasi(18,30,30);
obj1.cetak();

Waktu obj2 = new Waktu ();
obj2.inputWaktu();
obj2.cetak();

Waktu obj3 = new Waktu ();
obj3.hitungWaktu(obj1,obj2);
obj3.cetak();
}
}


2....
/*============================================================
Nama Program : Koordinat Tengah
Deskripsi : titik tengah Koordinat dengan OOP
=============================================================*/
class Point {
private float absis;
private float ordinat;

public Point(){
absis = 0;
ordinat = 0;
}

public void inisialisasi(float A, float B){
absis = A;
ordinat = B;
}

public void inputPoint(){
System.out.print("Absis : ");String str = BacaKeyboard.bacaString();
absis = Float.valueOf(str).floatValue();
System.out.print("Ordinat : ");str = BacaKeyboard.bacaString();
ordinat = Float.valueOf(str).floatValue();
}

public void cetak(){
System.out.println("(" + absis + ";" + ordinat + ")");

}
public void titikTengah(Point p1, Point p2){
absis = (p1.absis+p2.absis)/2;
ordinat=(p1.ordinat+p2.ordinat)/2;
}

}

public class Tengah{
public static void main(String[] args) {
Point satu = new Point();
System.out.print("Titik A ");
satu.inisialisasi(1,1);
satu.cetak();

Point dua = new Point();
System.out.println("Titik B ");
dua.inputPoint();
dua.cetak();

Point tiga = new Point();
System.out.println("Titik TENGAH ");
tiga.titikTengah(satu,dua);
tiga.cetak();

}
}