Adattípusok


Tipus.java: egész típusok
 
public class Tipus {
public static void main(String[] args) {
 byte b1=-128,b=0x41,b2=127;
 System.out.print("byte tipus: ");
 System.out.println("\tb1 = "+b1);
 System.out.println("\t\t\tb = "+b);
 System.out.println("\t\t\t\tb2 = "+b2);
 System.out.println();

 short s1=-32768,s=0x2a,s2=32767;
 System.out.print("short tipus: ");
 System.out.println("\ts1 = "+s1);
 System.out.println("\t\t\ts = "+s);
 System.out.println("\t\t\t\ts2 = "+s2);
 System.out.println();

 int i1=(int)(-Math.pow(2,31)),i=0xe1,i2=(int)(Math.pow(2,31)-1);
 System.out.print("int tipus: ");
 System.out.println("\ti1 = "+i1);
 System.out.println("\t\t\ti = "+i);
 System.out.println("\t\t\t\ti2 = "+i2);
 System.out.println("***********************************");
 System.out.println("* Integer.MIN_VALUE = "+Integer.MIN_VALUE+" *");
 System.out.println("* Integer.MAX_VALUE = "+Integer.MAX_VALUE+"  *");
 System.out.println("***********************************");

 long l1=(long)(-Math.pow(2,63)),l=160L,l2=(long)(Math.pow(2,63)-1);
 System.out.print("long tipus: ");
 System.out.println("\tl1 = "+l1);
 System.out.println("\t\t\tl = "+l);
 System.out.println("\t\t\t\tl2 = "+l2);
 System.out.println("*****************************************");
 System.out.println("* Long.MIN_VALUE = "+Long.MIN_VALUE+" *");
 System.out.println("* Long.MAX_VALUE = "+Long.MAX_VALUE+"  *");
 System.out.println("*****************************************");

 }
}


Tipus1.java: karakteres típus
 
public class Tipus1 {
public static void main(String[] args) {
 char c='\u002a',cA=(char)65,ca='a',caaWIN=(char)225,caaDOS=(char)160;
 System.out.print("char tipus: ");
 System.out.println("\tc = "+c+"\tcA = "+cA+"\tca = "+ca+
                    "\tcaaWIN = "+caaWIN+"\tcaaDOS = "+caaDOS);
 System.out.println();
 for(int i=32;i<128;i++) {
  System.out.print("(char)"+(i<100?" ":"")+i+" = "+(char)i+"   ");
  }
 System.out.println();
 }
}


Tipus2.java: logikai típus
 
public class Tipus2 {
public static void main(String[] args) {
 boolean bF=false,bT=true;
 System.out.print("boolean tipus: ");
 System.out.println("\tbF = "+bF+"\tbT = "+bT);
 System.out.println();

 int i,n=15;
 boolean paros;
 System.out.println("Az elso "+n+" egesz szam:");
 for(i=1;i<=n;i++) {
  if(i%2==0) paros=true;
  else paros=false;
  System.out.println("\t"+i+(paros?" (paros szam)":" (paratlan szam)"));
  }
 }
}


Tipus3.java: valós típusok
 
public class Tipus3 {
public static void main(String[] args) {
 float f1=(float)Math.PI,f=(float)1/3,f2=-1.5e11F;
 System.out.print("float tipus: ");
 System.out.println("\tf1 = "+f1);
 System.out.println("\t\t\tf = "+f);
 System.out.println("\t\t\t\tf2 = "+f2);
 System.out.println("**********************************");
 System.out.println("* Float.MIN_VALUE = "+Float.MIN_VALUE+"      *");
 System.out.println("* Float.MAX_VALUE = "+Float.MAX_VALUE+" *");
 System.out.println("**********************************");
 System.out.println();

 int n=2;
 f1=(float)Math.pow(10,n);
 f2=(long)(f*f1)/f1;
 System.out.println(f+" erteke "+n+" tizedesjeggyel: "+f2+" (kerekites nelkul)");
 f2=Math.round(f*f1)/f1;
 System.out.println(f+" erteke "+n+" tizedesjeggyel: "+f2+" (kerekitve)");
 System.out.println();

 double d1=Math.PI,d=2.0/3.0,d2=1.234e-21D;
 System.out.print("double tipus: ");
 System.out.println("\td1 = "+d1);
 System.out.println("\t\t\td = "+d);
 System.out.println("\t\t\t\td2 = "+d2);
 System.out.println("*********************************************");
 System.out.println("* Double.MIN_VALUE = "+Double.MIN_VALUE+"               *");
 System.out.println("* Double.MAX_VALUE = "+Double.MAX_VALUE+" *");
 System.out.println("*********************************************");
 System.out.println();

 n=4;
 d1=Math.pow(10,n);
 d2=(long)(d*d1)/d1;
 System.out.println(d+" erteke "+n+" tizedesjeggyel: "+d2+" (kerekites nelkul)");
 d2=Math.round(d*d1)/d1;
 System.out.println(d+" erteke "+n+" tizedesjeggyel: "+d2+" (kerekitve)");
 }
}


Tipus4.java: tömbök
 
public class Tipus4 {
public static void main(String[] args) {
 int i,n=5;
 double[] szam1=new double[n];
 for(i=0;i<n;i++) szam1[i]=Math.random();
 System.out.println(n+" darab veletlen valos szam a [0,1) intervallumbol:");
 for(i=0;i<n;i++) {
   System.out.println("A(z) "+(i+1)+". szam: "+szam1[i]);
   }

 int[] szam2=new int[n];
 for(i=0;i<n;i++) szam2[i]=(int)(Math.random()*90)+1;
 System.out.println(n+" darab veletlen egesz szam az [1,90] intervallumbol:");
 for(i=0;i<n;i++) {
   System.out.println("A(z) "+(i+1)+". szam: "+szam2[i]);
   }
 }
}

Boda István, 2005. március 30.