- Fundamental data types implemented directly by the C++ language
- Character types
- Integer types
- signed and unsigned
- Floating-point types
- Boolean type
- Size and precision is often compiler-dependent
- #include
<climits>
- #include
Type Sizes
- Expressed in bits
- The more bits the more values that can be represented
- The more bits the more storage required
| Size (in bits) | Representable Values | |
|---|---|---|
| 8 | 256 | 2^8 |
| 16 | 65,536 | 2^16 |
| 32 | 4,294,967,296 | 2^32 |
| 64 | 18,446,744,073,709,551,615 | 2^64 |
Character Types
- Used to represent single characters, ‘A’, ‘X’, ‘@’
- Wider types are used to represent wide character sets
| Type Name | Size / Precision |
|---|---|
| char | Exactly one byte. At least 8 bits. |
| char16_t | At least 16 bits. |
| char32_t | At least 32 bits. |
| wchar_t | Can represent the largest available character set |
Integer Types
| Type Name | Size / Precision |
|---|---|
| signed short int | At least 16 bits. |
| signed int | At least 16 bits. |
| signed long int | At least 32 bits. |
| signed long long int | At least 64 bits. |
| Type Name | Size / Precision |
|---|---|
| unsigned short int | At least 16 bits. |
| unsigned int | At least 16 bits. |
| unsigned long int | At least 32 bits. |
| unsigned long long int | At least 64 bits. |
- In addition to those shown in the table, it’s possible to store both signed and unsigned integers in the character data type
- If you want to declare a signed integer you don’t need to use the signed keyword, since by default integers are signed.
- Similarly, if you want an integer type that stores very large numbers, you can simply declare the type as long long. And you’ll get a signed long long integer.
- If you want unsigned integers, that is integers that are 0 or positive values only, then you’re required to use the unsigned keyword.
- By default, all integers are signed.
Floating-point Type
- Used to represent non-integer numbers
- Represented by mantissa and exponent (scientific notation)
- Precision is the number of digits in the mantissa
- Precision and size are compiler dependent
| Type Name | Size / Typical Precision | Typical Range |
|---|---|---|
| float | / 7 decimal digits | 1.2 x 10^-38 to 3.4 x 10^38 |
| double | No less than float / 15 decimal digits | 2.2 x 10^-308 to 1.8 x 10^308 |
| long double | No less than double/ 19 decimal digits | 3.3 x 10^-4932 to 1.2 x 10^4932 |
Boolean Type
- Used to represent true and false
- Zero is false
- Non-zero is true
| Type Name | Size / Precision |
|---|---|
| bool | Usually 8 bits true or false |
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