[Java005] Primitive 데이터 타입

public class PrimitiveVariable
{
  public static void printVariable(byte v)
  {
    System.out.println(v);
  }
 
  public static void printVariable(char v)
  {
    System.out.println(v);
  }
 
  public static void printVariable(boolean v)
  {
    System.out.println(v);
  }
 
  public static void printVariable(int v)
  {
    System.out.println(v);
  }
 
  public static void printVariable(long v)
  {
    System.out.println(v);
  }
 
  public static void printVariable(float v)
  {
    System.out.println(v);
  }
 
  public static void printVariable(double v)
  {
    System.out.println(v);
  }

 
  public static void main(String[] args)
  {
    printVariable((byte)1);
    printVariable('a');
    printVariable(true);
    printVariable(2);
    printVariable(3L);
    printVariable(4.0f);
    printVariable(5.0);
  }
}

출력결과
1
a
true
2
3
4.0
5.0

2. 변수의 정보

import java.lang.*;
import java.util.*;


public class PrimitiveVariable
{
  public static void infoVariable(Object v)
  {  
    if(v.getClass() == Boolean.class)
    {
      System.out.println("Boolean has no SIZE constant");
      System.out.println("Boolean has " + Boolean.TRUE + " and " + Boolean.FALSE);
    }
    else if(v.getClass() == Byte.class)
    {
      System.out.printf("Byte has %d bits\n", Byte.SIZE);
      System.out.printf("%d <= Byte <= %d\n", Byte.MIN_VALUE, Byte.MAX_VALUE);
    }
    else if(v.getClass() == Integer.class)
    {
      System.out.printf("Integer has %d bits\n", Integer.SIZE);
      System.out.printf("%d <= Integer <= %d\n", Integer.MIN_VALUE, Integer.MAX_VALUE);
    }
    else if(v.getClass() == Long.class)
    {
      System.out.printf("Long has %d bits\n", Long.SIZE);
      System.out.printf("%d <= Long <= %d\n", Long.MIN_VALUE, Long.MAX_VALUE);
    }
    else if(v.getClass() == Float.class)
    {
      System.out.printf("Float has %d bits\n", Float.SIZE);
      System.out.printf("%g <= Float <= %g\n", Float.MIN_VALUE, Float.MAX_VALUE);
    }
    else if(v.getClass() == Double.class)
    {
      System.out.printf("Double has %d bits\n", Double.SIZE);
      System.out.printf("%g <= Double <= %g\n", Double.MIN_VALUE, Double.MAX_VALUE);
    }
  }
 
  public static void main(String[] args)
  {
    infoVariable(new Boolean(true));
    infoVariable(new Byte((byte)1));
    infoVariable(new Integer(2));
    infoVariable(new Long(3L));
    infoVariable(new Float(4.0f));
    infoVariable(new Double(5.0 ));
  }
}

출력결과
Boolean has no SIZE constant
Boolean has true and false
Byte has 8 bits
-128 <= Byte <= 127
Integer has 32 bits
-2147483648 <= Integer <= 2147483647
Long has 64 bits
-9223372036854775808 <= Long <= 9223372036854775807
Float has 32 bits
1.40130e-45 <= Float <= 3.40282e+38
Double has 64 bits
4.90000e-324 <= Double <= 1.79769e+308