Java Typecasting

---

---

What is type casting in java?

The process of converting one data type value to another data type value is called casting. Type casting is useful when we want to convert one value into another like string 123 into integer 123.

Type casting refers to changing a type of one data type into another. If you store an int value into a byte variable directly, this will be given as illegal operation.

---

Syntax of typecasting

type variable1 = (new_type) variable2;

Example

 int x = 20;	
 byte b = (byte) x;

In above example, the variable x is a type of integer variable and we have converted it into the byte variable using type casting

---

Problems while type casting

Casting of large data type into smaller type may result in a loss of data. It is always better to cast smaller type into larger.

Example of loss of data

 int x = 130;
 byte b = (byte) x;

In above example the integer variable x having range 2,147,483,647 for storing a value. but the byte variable have only 127.

130-127 = 3 data is lost in the conversion.

---

There is no loss of data from below conversion

Type	Converted into
byte	short,char,int,float,double
short	int,float,double,long
char	int,float,double,long
int	float,double,long
long	float,double
float	double

---

Narrowing type casting

The process of assigning a larger type to a smaller type is known as narrowing, which causes loss of data.

Example -

class Narrowing
{
   public static void main(String args[])
   {
      int int_value = 32569;
      byte byte_value;

      byte_value = (byte ) int_value;

      System.out.println("Integer : "+int_value);
      System.out.println("Byte : "+byte_value);
   }
}

Output

---

Widening type casting

Process of assigning smaller data type value to larger data type is known as widening. The data will not loss in widening.

Example

class Widening
{
   public static void main(String args[])
   {
      short old_salary = 30000;
      short salary_increased = 15000;
      int new_salary = (int) (old_salary + salary_increased));

      System.out.println("old salary : "+old_salary);
      System.out.println("salary increased by : "+salary_increased);
      System.out.println("new salary is : "+new_salary);
   }
}

Output

---

Automatic type conversion

For assigning one type of data values to another type of data variables, casting is required. But java also provides without casting conversion known as automatic type conversion.

If data type is large enough to hold value of source value, then type casting is not required.

Example

class AutotypeConversion
{
   public static void main(String args[])
   {
      short machine_cost = 9000;
      byte offer_given = 120;
      int new_price = machine_cost - offer_given ;

      System.out.println("Machine cost : "+machine_cost);
      System.out.println("New Machine cost : "+new_price);
   }
}

---