Type Conversion in Expressions

AUTOMATIC TYPE CONVERSION

     An expression is defined as a linear combination of operands and operators. If the operands are of different data types (int, float etc) the lower data type operand is automatically converted to the higher data type before execution. This process of conversion is called automatic type conversion. The result is of the higher type.

Example

Let,

     float b=10.7;

     int c=7;

Then b+c=17.7. here int c is converted to float.

The table given below shows the conversion.

datatype	Char	byte	short	int	long	float	double
char short Int long float double	int int int long float double	int int int long float double	int int int long float double	int int int long float double	long long long long float double	float float float float float double	double double double double double double

   

     Even though the result of the expression is converted to higher data type, the result depends on the data type of the variable on the left hand side of the expression.

Example

     int a;

     float b=10.7;

     int c=7;

     a=b+c;

The value stored in a is 17

CASTING A VALUE

     The process of converting the data type of an operand in an expression locally without affecting its data type in the declaration is called casting a value. The general form is

     (datatype)expression

Where             datatype     -     valid datatype

                       Expression -     valid expression

Example

1.       (int)(x+y)     - The result of expression a+b is converted to integer.

2.       (int)10.9       - 10.9 is converted to integer 10.

3.       (float)x+y    - x is converted to float and is added to y.