In this I will learn about data types, Before that I will understand what Is variables and keywords.
Variable – It a place where we store some memory at a place where we allocated it.
- A variable can have alphabets, digits, underscore.
- Variable can’t start with digits.
- No whitespace is allowed within the variable name.
- A variable can’t be reserved work or keyword like int etc.
Types of Variables
- Local Variables
- Instance Variables
- Static Variables
Data types are mainly divided into three types:
- Primitive Data Types: These are built – in or predefined data types and can be used directly by the user to declare variables.
- Integer(int)
- Floating point(float)
- Character(char)
- Boolean(bool)
- Double Floating Point
- Void (value less)
- Wide Character
2. Derived Data Types: These are the data types that are derived from the primitive or build in datatypes.
- Function
- Array
- Pointer
- Reference
3. User Defined : These are data types which we can defined by ourself. Like Defining a class inC++ or a structure.
- Class
- Structure
- Union
- Enumeration
- Typedef Define DataType
// c++ program to size of data types
#include <iostream>
using namespace std;
int main()
{
cout << "Size of char : " << sizeof(char) << " byte" << endl;
cout << "Size of int : " << sizeof(int) << " bytes" << endl;
cout << "Size of short int : " << sizeof(short int) << " bytes" << endl;
cout << "Size of long int : " << sizeof(long int) << " bytes" << endl;
cout << "Size of signed long int : " << sizeof(signed long int) << " bytes" << endl;
cout << "Size of unsigned long int : " << sizeof(unsigned long int) << " bytes" << endl;
cout << "Size of float : " << sizeof(float) << " bytes" <<endl;
cout << "Size of double : " << sizeof(double) << " bytes" << endl; cout << "Size of wchar_t : " << sizeof(wchar_t) << " bytes" <<endl;
return 0;
}
Output
Size of char : 1 byte
Size of int : 4 bytes
Size of short int : 2 bytes
Size of long int : 8 bytes
Size of signed long int : 8 bytes
Size of unsigned long int : 8 bytes
Size of float : 4 bytes
Size of double : 8 bytes
Size of wchar_t : 4 bytes