3. Integer Data

There are 4 Java primitives dealing with integer data. The difference is the number of bytes: 1, 2, 4 or 8. The number of bits is the number of bytes multiplied by 8-bits.

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byte is 8-bits and can represent a number between -128 to +127. If we try to represent 128, which is out of range, it will be seen as -128.

  // *** 1. Start (8-bits, -128 to +127)
  byte b1 = 5;
  byte b2 = -5;
  byte b3 = (byte)128;
  System.out.println("b3 = " + b3);
  // *** 1. End

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short is 16-bits and can represent a number between -32,768 to +32,767. Again, we can see that representing 32,768, which is out-of-range, is seen as -32,768.

  // *** 2. Start (16-bits, -32768 to 32767)
  short s1 = 5_000;
  short s2 = -5_000;
  short s3 = (short)32768;
  System.out.println("s3 = " + s3);
  // *** 2. End

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int is 32-bits and can represent a number between -2^31 to +2^31-1. Any underscores in numbers are ignored.

  // *** 3. Start (32-bits, -2,147,483,648 to
  // ***                    +2,147,483,647)
  int i1 = 5_000_000;
  int i2 = -5_000_000;
  int i3 = 2_147_483_647 + 1;
  System.out.println("i3 = " + i3);
  // *** 3. End

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long is 64-bits and can represent a number between -2^63 to +2^63-1. To represent a large number you have to put L at end of number, since the default is integer with a lower range. You can also use lower-case letter l but it looks too much like the number 1.

  // *** 4. Start (64-bits)
  // ***    (From -9223372036854775808 to
  // ***          +9223372036854775807)
  long l1 = 50_000_000_000L;
  long l2 = 50000000000L;
  System.out.println("l2-l1 = " + (l2-l1));
  // *** 4. End

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package com.javaAndroid.ex3;

public class Ex3 {
 public static void main(String[] args) {
  // *** 1. Start (8-bits, -128 to +127)
  byte b1 = 5;
  byte b2 = -5;
  byte b3 = (byte)128;
  System.out.println("b3 = " + b3);
  // *** 1. End
  // *** 2. Start (16-bits, -32768 to 32767)
  short s1 = 5_000;
  short s2 = -5_000;
  short s3 = (short)32768;
  System.out.println("s3 = " + s3);
  // *** 2. End
  // *** 3. Start (32-bits, -2,147,483,648 to
  // ***                    +2,147,483,647)
  int i1 = 5_000_000;
  int i2 = -5_000_000;
  int i3 = 2_147_483_647 + 1;
  System.out.println("i3 = " + i3);
  // *** 3. End
  // *** 4. Start (64-bits)
  // ***    (From -9223372036854775808 to
  // ***          +9223372036854775807)
  long l1 = 50_000_000_000L;
  long l2 = 50000000000L;
  System.out.println("l2-l1 = " + (l2-l1));
  // *** 4. End
 }
}

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