In this tutorial you will learn about the C++ Data Type Modifiers and its application with practical example.
C++ Data Type Modifiers
In C++, modifiers is used to modify or add special meaning to the base types. It is used as prefix to primitive data types to alter their predefined meaning.
In C++, we have following data type modifiers –
- signed
- unsigned
- long
- short
The modifiers can be used with primitive data types to make them more precise and to modify their range.
Integer Type Modifiers
The signed, unsigned, long, and short modifiers can be used with integer types. The signed and unsigned modifiers can also be used as prefix to long or short modifiers. For example, unsigned long int.
| Type | Approximate Size (in byte) |
Minimal Range |
|---|---|---|
| short | 2 | -32768 to 32767 |
| unsigned short | 2 | 0 to 65,535 |
| signed short | 2 | same as short |
| int | 2 | -32768 to 32767 |
| unsigned int | 2 | 0 to 65,535 |
| signed int | 2 | same as int |
| long | 4 | -2,147,483,648 to 2,147,483,647 |
| unsigned long | 4 | 0 to 4,294,967,295 |
| signed long | 4 | same as long |
Character Type Modifiers
The signed and unsigned modifiers can be applied to char type.
| Type | Approximate Size (in bytes) |
Minimal Range |
|---|---|---|
| char | 1 | -128 to 127 |
| unsigned char | 1 | 0 to 255 |
| signed char | 1 | same as char |
Float Type Modifiers
The long modifier can be applied to double type.
| Type | Approximate Size (in bytes) |
Minimal Range | Digits of Precision |
|---|---|---|---|
| float | 4 | 3.4 × 10-38 to 3.4 × 1038 – 1 | 7 |
| double | 8 | 1.7 × 10-308 to 1.7 × 10308 – 1 | 15 |
| long double | 10 | 3.4 × 10-4932 to 3.4 × 104932 – 1 | 19 |
Type Qualifiers in C++
In C++, type qualifiers are used to provide additional information about the variables.
| Qualifier | Meaning |
|---|---|
| const | Objects of type const cannot be changed by your program during execution |
| restrict | A pointer qualified by restrict is initially the only means by which the object it points to can be accessed. Only C99 adds a new type qualifier called restrict. |
| volatile | The modifier volatile tells the compiler that a variable’s value may be changed in ways not explicitly specified by the program. |
