// atoi example 
// source: http://www.cplusplus.com/

#include <stdio.h>
#include <stdlib.h> 

#define SIZE 256

int main()
{
  int i;
  char buffer[SIZE];
  printf ("Enter a number: ");
  // read a number as a  string "1900" 
  fgets(buffer, sizeof(buffer), stdin);
  // now convert it to a numerical value and store in integer
  // now the string "1900" is coverted to an numerical value 1900 
  // stored in i
  i = atoi(buffer);
  printf ("The value entered is %d. Its double is %d.\n",i,i*2);
  return EXIT_SUCCESS;
}