libex1.c

/* 
  file: libex1.c
  author: David De Potter
  description: example program using functions from clib library
    Program asks for a pos. integer and prints some of its properties
  compilation: ../ctest.sh libex1.c
  usage: ./a.out
*/

#include "clib/clib.h"

int isValidInt(char *str, int *n) {
  // check if the input is a valid positive integer
  char *end;
  if (str[strlen(str) - 1] != '\n') {  
    // if the input is too long, clear stdin buffer
    while (getchar() != '\n');         
    return 0;
  }
  // try to convert the input to an int
  *n = strtol(str, &end, 10);
  // return 1 if the input was fully converted to a pos int
  return *end == '\n' && *n > 0;      
}

int main() {
  char input[11];
  int n;

  while (1) {
    printf("\nGive a positive integer of at most 9 digits (q to quit): ");
    if (! fgets(input, 11, stdin) || input[0] == 'q')
      break;
    // check if the input is valid
    if (! isValidInt(input, &n)) {
      printf("Invalid input\n");
      continue;
    }
    
    // print some properties of the input number
    char *bin = toBinary(n);
    int nDigits = countDigits(n);
    printf("The input has %d digit%s.\n"
           "The number is %sa prime.\n"
           "It is %sa perfect square.\n"
           "Its reverse is %d.\n"
           "Its binary representation is %s, which is %sa palindrome.\n",
           nDigits, nDigits == 1 ? "" : "s",
           isPrime(n) ? "" : "not ",
           isPerfSquare(n) ? "" : "not ",
           reverseInt(n), 
           bin, isStrPalindrome(bin, bin + strlen(bin) - 1) ? "" : "not ");
    free(bin);
  }
  return 0;
}