Program to understand STATIC variable

Static is multipurpose keyword, we can use static in context of variable, function and classes.
Here we discuss about the static variable.
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//In this program we are not using static variable 
 #include<stdio.h>
#include<conio.h>

void show()
{
    int i=0;          //Note, we are not declaring 'i' as a static variable here
    i++;               //variable 'i' increased by 1

    printf("output is %d\n" ,i);
}

void main()
{
    show();            //here we are calling show 3 times
    show();
    show();
}

output:
       output is 1
       output is 1
       output is 1

You can see that  output is 1, although we are calling show function 3 time.
That because the variable i not retaining the value.

•  So to retain the value we use this variable as a static variable. (see next program)

•  Static variable is useful when we want to count the no of attempt performed by the client. (see last program)

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//using STATIC variable
#include<stdio.h>
#include<conio.h>

int show()
{
    static int i=0;            //here we use static variable
             i++;
             printf("output is %d\n" ,i);
}

void main()
{
    show();
    show();
    show();
}

output:
          output is 1
          output is 2
          output is 3
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//In this program we want that user have only 4 chance to enter right password
#include<iostream>
#include<string>
#include<stdlib.h>              //for exit(0);
using namespace std;

int show()
{
     static int i=0;            //here we use static variable
           // int i=0;

     string password;           
     i++;
                      
            if(i<=3)
            {
                cout << "\nenter your password: ";
                cin >> password;
               
                if (password == "foobar")
                    {
                        cout << "\nwelcome you log in!\n";
                        exit(0);
                    }
            }
  
            else
            {
                cout << "recover your password";
            }
           
}

int main()
{
    show();              //here we can use the loop also
    show();
    show();
    show();
}