Saturday 29 August 2015

Type Casting

Type Casting

Assigning a value of one type to a variable of another type is known as Type Casting.
Example :
int x = 10;
byte y = (byte)x;
In Java, type casting is classified into two types,
  • Widening Casting(Implicit)
  • widening-type-conversion
  • Narrowing Casting(Explicitly done)
  • narrowing-type-conversion

Widening or Automatic type converion

Automatic Type casting take place when,
  • the two types are compatible
  • the target type is larger than the source type
Example :
public class Test
{
    public static void main(String[] args)
    {
      int i = 100; 
      long l = i; //no explicit type casting required  
      float f = l; //no explicit type casting required  
      System.out.println("Int value "+i);
      System.out.println("Long value "+l);
      System.out.println("Float value "+f);
    }
    
}
Output :
Int value 100
Long value 100
Float value 100.0

Narrowing or Explicit type conversion

When you are assigning a larger type value to a variable of smaller type, then you need to perform explicit type casting.
Example :
public class Test
{
    public static void main(String[] args)
    {
      double d = 100.04;  
      long l = (long)d;  //explicit type casting required  
      int i = (int)l; //explicit type casting required  
      
      System.out.println("Double value "+d);
      System.out.println("Long value "+l);
      System.out.println("Int value "+i);
     
    }
    
}
Output :
Double value 100.04
Long value 100
Int value 100

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