C++ Data Types

In this tutorial, we will learn about basic data types such as int, float, char, etc. in C++ programming with the help of examples. 
 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 Type 
 Meaning 
 Size (in Bytes) 
 
 
 int 
 Integer 
 2 or 4 
 
 
 float 
 Floating-point 
 4 
 
 
 double 
 Double Floating-point 
 8 
 
 
 char 
 Character 
 1 
 
 
 wchar_t 
 Wide Character 
 2 
 
 
 bool 
 Boolean 
 1 
 
 
 void 
 Empty 
 0 
 
 
 
 
 
 
 
 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. 
 
 
 
 
 
 Putting it all together 
 Run the following repl to see its results. Looking at the main.cpp file, a range of variables of different data types are declared at the top. 
 cout is used with the + operator to output the sum of two integers. cout is also used to display a message that includes the contents of the string variables, and lastly an if statement is used to present a message based on which letter is stored in the char variable. 
 Try doing each of the following, running the between each change: 
 
 Change the string variables to reflect your name 
 Change the values of the integers 
 Change the operator used in the output to * 
 Change the letter stored in the char variable to a grade you would like to receive 
 Change the integer variables to float, and assign decimal values. 
 
 
 
 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 Type 
 Size (in Bytes) 
 Meaning 
 
 
 signed int 
 4 
 used for integers (equivalent to int ) 
 
 
 unsigned int 
 4 
 can only store positive integers 
 
 
 short 
 2 
 used for small integers (range -32768 to 32767 ) 
 
 
 unsigned short 
 2 
 used for small positive integers (range 0 to 65,535 ) 
 
 
 long 
 at least 4 
 used for large integers (equivalent to long int ) 
 
 
 unsigned long 
 4 
 used for large positive integers or 0 (equivalent to unsigned long int ) 
 
 
 long long 
 8 
 used for very large integers (equivalent to long long int ). 
 
 
 unsigned long long 
 8 
 used for very large positive integers or 0 (equivalent to unsigned long long int ) 
 
 
 long double 
 12 
 used for large floating-point numbers 
 
 
 signed char 
 1 
 used for characters (guaranteed range  -127 to 127 ) 
 
 
 unsigned char 
 1 
 used 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.