The type conversion is the process by
which one data typed variable value is converted into other data typed variable
value. For example an int data type is
converted into a float data type, etc.
There can be two kinds of type
conversion.
1. Implicit Conversion
2. Explicit Conversion
- Implicit Conversion:
This type of
conversion takes place automatically when the following conditions are
satisfied.
1. Destination variable type and source
variable type are compatible.
2. Size of destination type of variable
is large enough to hold the values of source type variable.
Consider the below figure, u can
see float labeled box is larger than the int box and int box is larger than
byte box. The smaller box can occupy in bigger box but other way, that is
larger into smaller is not possible.
Code fragment showing implicit conversion
byte b=20; // declare a byte variable
int a=b; // byte is converted and stored in
int.
int a=68; // declare
int
long lng=a; //int is
converted and stored in long.
Example Program for Implicit Type
Conversion:
/** Program for Implicit type conversion
*
* @author Jaivanth
*
*/
public class
SampleImplicitTypeConversion
{
public static void main(String[] args)
{
byte b=20;// declare byte.
char ch='A';// character declared
int a=b;// implicit type
conversion.
int z=ch; // char assigned to z
System.out.println("Value of z is
"+z);
float f=a;//implicit type
conversion.
double db=b+a+f+ch; // implicit type
conversion in expression.
System.out.println("value of double is
"+db);
}
}
Output:
Value
of z is65
value
of double is125.0
- Explicit Conversion:
This type of conversion takes place
between the incompatible types. For example, conversion from int to byte or
float to int. This conversion is not possible automatically. In order achieve
explicit conversion you should use ‘cast’.
Code fragments showing type casting:
int a=10; //declared int variable.
byte b=(byte)a; //int value converted to byte
value using cast and stored in byte.
Float f=20.58; //declared float.
int a=(int)f; // float value type casted and
stored in int.
Example Program for Explicit Type
Conversion:
/** program for explicit type conversion
*
* @author Jaivanth
*
*/
public class
SampleExplicitTypeConversion
{
public static void main(String[] args)
{
double db=65.69;// double declared
int a=(int)db;// type casting from double to int
char ch=(char)a;// type casting from int to char
byte b=(byte)a; // type casting from int to byte
int z=a+ch+b; // dynamic initialization
System.out.println("Value of db is
"+db);
System.out.println("Value of ch is
"+ch);
System.out.println("Value of a is
"+a);
System.out.println("Value of b is
"+b);
System.out.println("Value of z is
"+z);
}
}
Output:
Value
of db is 65.69
Value
of ch is A
Value
of a is 65
Value
of b is 65
Value
of z is 195
