Design and test a C program to demonstrate storage classes


// A C program to demonstrate different storage
// classes
#include <stdio.h>

// declaring the variable which is to be made extern
// an initial value can also be initialized to x
int x;

void autoStorageClass()

printf("\nDemonstrating auto class\n\n");

// declaring an auto variable (simply
// writing "int a=32;" works as well)
auto int a = 32;

// printing the auto variable 'a'
printf("Value of the variable 'a'"
" declared as auto: %d\n",


void registerStorageClass()

printf("\nDemonstrating register class\n\n");

// declaring a register variable
register char b = 'G';

// printing the register variable 'b'
printf("Value of the variable 'b'"
" declared as register: %d\n",


void externStorageClass()

printf("\nDemonstrating extern class\n\n");

// telling the compiler that the variable
// x is an extern variable and has been
// defined elsewhere (above the main
// function)
extern int x;

// printing the extern variables 'x'
printf("Value of the variable 'x'"
" declared as extern: %d\n",

// value of extern variable x modified
x = 2;

// printing the modified values of
// extern variables 'x'
printf("Modified value of the variable 'x'"
" declared as extern: %d\n",


void staticStorageClass()
int i = 0;

printf("\nDemonstrating static class\n\n");

// using a static variable 'y'
printf("Declaring 'y' as static inside the loop.\n"
"But this declaration will occur only"
" once as 'y' is static.\n"
"If not, then every time the value of 'y' "
"will be the declared value 5"
" as in the case of variable 'p'\n");

printf("\nLoop started:\n");

for (i = 1; i < 5; i++)

// Declaring the static variable 'y'
static int y = 5;

// Declare a non-static variable 'p'
int p = 10;

// Incrementing the value of y and p by 1

// printing value of y at each iteration
printf("\nThe value of 'y', "
"declared as static, in %d "
"iteration is %d\n",
i, y);

// printing value of p at each iteration
printf("The value of non-static variable 'p', "
"in %d iteration is %d\n",
i, p);

printf("\nLoop ended:\n");


int main()

printf("A program to demonstrate"
" Storage Classes in C\n\n");

// To demonstrate auto Storage Class

// To demonstrate register Storage Class

// To demonstrate extern Storage Class

// To demonstrate static Storage Class

// exiting
printf("\n\nStorage Classes demonstrated\n");

return 0;


big output i know but try to understand by doing :)