CPP Tutorial

CPP examples programs

CPP Storage Classes

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A Storage class in CPP represents the scope of a variable within the program. The storage classes in CPP are discussed below:

 

Storage Classes Storage Place Default Value Scope Life-time Features
auto RAM Garbage Local Within function Default storage class.
extern RAM 0 Global Till the end of main program Visible to all the programs.
static RAM 0 Local Till the end of main program Retains value between multiple functions call.
register Register Garbage Local Within function Faster access than other variables.
mutable – Garbage Local Within Class Used only for class data members.

 

Example:

#include <iostream.h>
using namespace std;
 
int demo()
{    
static int i=0;
register int j=0;
auto k=0;
i++;    
j++;
k++;
cout << "i = " << i << endl;    
cout << "j = " << j << endl;    
cout << "k = " << k << endl;   
return 0;
}  
int main()
{    
demo();   
demo();   
demo();  
return 0;
}

Output

i = 1
j = 1
k = 1
i = 2
j = 1
k = 1
i = 3
j = 1
k = 1