The process of
converting one data type to another is called as type casting. Type casting
becomes unavoidable on many occasions. Type casting is done to take advantage
of certain features of type hierarchies.
Type casting is of
types,
- Implicit type casting
- Explicit type casting
The term used for
implicit type casting is coercion. The most common form of explicit type
casting is called as casting. Explicit type casting can also be achieved with
independently defined conversion routines for example overloading object
constructor.
Implicit type
casting
Implicit type
casting, also known as coercion is an automatic type casting by the compiler.
Some languages allow, or even require, compliers to provide implicit type
casting. In a mixed-type expression, the program will execute properly if the
data of one or more subtype can be converted to a super type.
Example:
short num1=1000;
int num2;
num2=num1;
In the above
example, the value of “a” i.e. short has been promoted to type int without
using any type casting operator. This is called as standard type casting.
Standard type casting affects fundamental data types. When working with
floating point numbers, sometime these conversions may imply a loss of
precision, where the complier will show a warning. This can be avoided with an
explicit type casting.
Explicit type
casting
A lot of
conversions, especially those that imply a different interpretation of the
value, require explicit type casting.
Example:
short num1=1000;
int num2;
num2= (int) num1;
//cast notation
num2=int(a);
//functional notation
Explicit conversion
of several kinds like checked, unchecked or bit pattern.
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