#include <stdio.h>
#include <string.h>

#define MAX      100000
#define CRORE    7
#define LAKH     5
#define THOUSAND 3
#define HUNDRED  2
#define TEN      1

/* returns inside str[] the word corresponding to single digit 1-9 */
void unitString ( int n, char str[ ] )
{
  switch(n) {
    case 0: strcpy(str, "");       break;
    case 1: strcpy(str, " one");   break;
    case 2: strcpy(str, " two");   break;
    case 3: strcpy(str, " three"); break;
    case 4: strcpy(str, " four");  break;
    case 5: strcpy(str, " five");  break;
    case 6: strcpy(str, " six");   break;
    case 7: strcpy(str, " seven"); break;
    case 8: strcpy(str, " eight"); break;
    case 9: strcpy(str, " nine");  break;
  }
}

/* returns inside str[] the word corresponding to teen digits 11-19 */
void teenString ( int n, char str[ ] )
{
  switch(n) {
    case 0: strcpy(str, "");           break;
    case 1: strcpy(str, " eleven");    break;
    case 2: strcpy(str, " twelve");    break;
    case 3: strcpy(str, " thirteen");  break;
    case 4: strcpy(str, " fourteen");  break;
    case 5: strcpy(str, " fifteen");   break;
    case 6: strcpy(str, " sixteen");   break;
    case 7: strcpy(str, " seventeen"); break;
    case 8: strcpy(str, " eighteen");  break;
    case 9: strcpy(str, " nineteen");  break;
  }
}

/* returns inside str[] the word corresponding to tens digits 10,20,30,40,50,60,70,80,90 */
void tensString ( int n, char str[ ] )
{
  switch(n) {
    case 0: strcpy(str, "");         break;
    case 1: strcpy(str, " ten");     break;
    case 2: strcpy(str, " twenty");  break;
    case 3: strcpy(str, " thirty");  break;
    case 4: strcpy(str, " forty");   break;
    case 5: strcpy(str, " fifty");   break;
    case 6: strcpy(str, " sixty");   break;
    case 7: strcpy(str, " seventy"); break;
    case 8: strcpy(str, " eighty");  break;
    case 9: strcpy(str, " ninety");  break;
  }
}

/* handles word generation for two consecutive digits */
void genTwoDigitString ( char num[ ], int l, char str[ ], int b )
{
  char s[MAX];
  int teenFlag = 0;

  s[0] = '\0';
  if ( l > b ) {
    if ( (num[l-b-1]-'0' == 1) && (num[l-b]-'0' > 0) )
      teenFlag = 1;
    else {
      tensString(num[l-b-1]-'0', s);
      strcat(str, s);
    }
  }

  s[0] = '\0';
  if ( l > b-1 ) {
    if ( teenFlag ) {
      teenString(num[l-b]-'0', s);
      teenFlag = 0;
    }
    else
      unitString(num[l-b]-'0', s);
    strcat(str, s);
  }
}

/* handles word generation within every crore boundaries */
void genBoundedWordString ( char num[ ], int l, char str[ ] )
{
  char s[MAX];

  /* handle numbers inside 100000-9999999 */
  s[0] = '\0';
  genTwoDigitString (num, l, s, LAKH+1);
  if ( l > LAKH && s[0] != '\0' ) {
    strcat(str, s);
    strcat(str, " lakh");
  }

  /* handle numbers inside 1000-9999 */
  s[0] = '\0';
  genTwoDigitString (num, l, s, THOUSAND+1);
  if ( l > THOUSAND && s[0] != '\0' ) {
    strcat(str, s);
    strcat(str, " thousand");
  }

  /* handle numbers inside 100-999 */
  s[0] = '\0';
  if ( l > HUNDRED ) {
    unitString(num[l-HUNDRED-1]-'0', s);
    if ( s[0] != '\0' ) {
      strcat(str, s);
      strcat(str, " hundred");
    }
  }

  /* handle numbers inside 1-99 */
  s[0] = '\0';
  genTwoDigitString (num, l, str, TEN);
}

/* generates the word string corresponding to the full number */
void numToWordString ( char num[ ], int l, char str[ ] )
{
  if ( l > CRORE ) {
    numToWordString(num, l-CRORE, str); // recursive call across crore boundaries
    strcat(str, " crore");
  }
  genBoundedWordString(num, l, str); // handle number inside each crore
}

/* generates the digit string corresponding to each digit in the full number */
void numToDigitString ( char num[ ], int l, char str[ ] )
{
  char s[MAX];

  if ( l > 0 ) {
    numToDigitString(num, l-1, str);
    s[0] = '\0';
    unitString(num[l-1]-'0', s);
    if ( s[0] != '\0' )
      strcat(str, s);
    else
      strcat(str, " zero");
  }
}

int main ()
{
  char number[MAX], string[MAX];

  printf("Enter Number: ");
  scanf("%s", number);

  string[0] = '\0';
  numToDigitString(number, strlen(number), string);
  printf("\nDigit Sequence: %s\n", string);

  string[0] = '\0';
  numToWordString(number, strlen(number), string);
  printf("\nNumber in Word: %s\n", string);

  return 0;
}