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):
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.
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
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