How to Copy a long Java Variable Into an int

You might think that you could copy a long variable into an int variable like this:

 

Solaris > cat prog10.java

public class prog10

{

public static void main (String args[])

  {

  int a;

  long b = 100;

  a = b;

  System.out.println ("a = " + a);

  System.out.println ("b = " + b);

  }

}

Solaris >

 

… but you get a compilation error if you try:

 

Solaris > javac prog10.java

prog10.java:7: possible loss of precision

found   : long

required: int

  a = b;

      ^

1 error

Solaris >

 

You have to do it like this instead:

 

Solaris > cat prog11.java

public class prog11

{

public static void main (String args[])

  {

  int a;

  long b = 100;

  a = (int) b;

  System.out.println ("a = " + a);

  System.out.println ("b = " + b);

  }

}

Solaris > javac prog11.java

Solaris > java prog11

a = 100

b = 100

Solaris >

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How Big (or Small) Can a Java Long Integer Be?

Java long variables let you store even larger numbers. The program below shows how you can display the maximum and minimum values allowed:

UBUNTU > cat prog9.java
public class prog9
{
public static void main (String args[])
  {
  System.out.println
  ("The largest long you can have is " + Long.MAX_VALUE );
  System.out.println
  ("The smallest long you can have is " + Long.MIN_VALUE );
  }
}
UBUNTU > javac prog9.java
UBUNTU > java prog9
The largest long you can have is 9223372036854775807
The smallest long you can have is -9223372036854775808
UBUNTU > 

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