Renz M.Arcosiba.
CHS-2B
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C++ Data Types
In C++, data types are declarations for variables. This determines the
type and size of data associated with variables. For example,
int age = 13;
Here, age is a variable of type int. Meaning, the variable can only store
integers of either 2 or 4 bytes.
C++ Fundamental Data Types
The table below shows the fundamental data types, their meaning, and their
sizes (in bytes):
Data TypeMeaningSize (in Bytes)intInteger2 or 4floatFloating-
point4doubleDouble Floating-point8charCharacter1wchar_tWide
Character2boolBoolean1voidEmpty0
Now, let us discuss these fundamental data types in more detail.
1. C++ int
The int keyword is used to indicate integers.
Its size is usually 4 bytes. Meaning, it can store values from -2147483648
to 2147483647.
For example,
int salary = 85000;
2. C++ float and double
float and double are used to store floating-point numbers (decimals and
exponentials).
The size of float is 4 bytes and the size of double is 8 bytes.
Hence, double has two times the precision of float. To learn more, visit
C++ float and double.
For example,
float area = 64.74; double volume = 134.64534;
As mentioned above, these two data types are also used for exponentials.
For example,
double distance = 45E12 // 45E12 is equal to 45*10^12
3. C++ char
Keyword char is used for characters.
Its size is 1 byte.
Characters in C++ are enclosed inside single quotes ' '.
For example,
char test = 'h';
Note: In C++, an integer value is stored in a char variable rather than
the character itself. To learn more, visit C++ characters.
4. C++ wchar_t
Wide character wchar_t is similar to the char data type, except its size
is 2 bytes instead of 1.
It is used to represent characters that require more memory to represent
them than a single char.
For example,
wchar_t test = L' 'ם// storing Hebrew character;
Notice the letter L before the quotation marks.
Note: There are also two other fixed-size character
types char16_t and char32_t introduced in C++11.
5. C++ bool
The bool data type has one of two possible values: true or false.
Booleans are used in conditional statements and loops (which we will learn
in later chapters).
For example,
bool cond = false;
6. C++ void
The void keyword indicates an absence of data. It means "nothing" or "no
value".
We will use void when we learn about functions and pointers.
Note: We cannot declare variables of the void type.
C++ Type Modifiers
We can further modify some of the fundamental data types by using type
modifiers. There are 4 type modifiers in C++. They are:
signed
unsigned
short
long
We can modify the following data types with the above modifiers:
int
double
char
C++ Modified Data Types List
Data TypeSize (in Bytes)Meaningsigned int4used for integers (equivalent to
int)unsigned int4can only store positive integersshort2used for small
integers (range -32768 to 32767)unsigned short2used for small positive
integers (range 0 to 65,535)longat least 4used for large integers
(equivalent to long int)unsigned long4used for large positive integers or
0 (equivalent to unsigned long int)long long8used for very large integers
(equivalent to long long int).unsigned long long8used for very large
positive integers or 0 (equivalent to unsigned long long int)long
double12used for large floating-point numberssigned char1used for
characters (guaranteed range -127 to 127)unsigned char1used for characters
(range 0 to 255)
Let's see a few examples.
long b = 4523232; long int c = 2345342; long double d = 233434.56343;
short d = 3434233; // Error! out of range unsigned int a = -5; // Error!
can only store positive numbers or 0
Derived Data Types
Data types that are derived from fundamental data types are derived types.
For example: arrays, pointers, function types, structures, etc.
We will learn about these derived data types in later tutorials.
