data types used in c++ language

Fundamental data types
int , char, float, double , bool, void etc
Derived data types
array , pointer etc.

User defined data types
structure, union, enum and class etc.
c++ modifier   
signed, unsigned short, long

char                 1 byte       
int                    2/4 byte    (depends on your system configuration)   
signed int        2 byte       
unsigned int    2 byte       
short int          2 byte       
long int          4 byte
float               4 byte
double           8 byte
long double  10 byte

programme to display the size of data types in c++

#include <iostream>
#include <iomanip>
using namespace std;
int main() {
   cout << "Size of char : " << sizeof(char) << endl;
   cout << "Size of int : " << sizeof(int) << endl;
   cout << "Size of short int : " << sizeof(short int) << endl;
   cout << "Size of long int : " << sizeof(long int) << endl;
   cout << "Size of float : " << sizeof(float) << endl;
   cout << "Size of double : " << sizeof(double) << endl;
   cout << "Size of wchar_t : " << sizeof(wchar_t) << endl;
   double b=1.2345678912345678912345;
   cout<<b;
   cout<<endl;
   cout<< setprecision(12)<<b;
   cout<<endl;
   wchar_t w  = L'A';
   cout << "Wide character value:: " << w << endl ;
   cout << "Size of the wide char is:: " << sizeof(w);
   return 0;
}