C Program to convert number to words

number_to_words.c

#include<stdlib.h>
#include<stdio.h>
void main() {
  long num, div, n1;
  int flag, digit, pos, tot_dig;
  
  printf("\nEnter a number: ");
  scanf("%ld", &num);
    
	if(num == 0) {
    printf("Zeron\n");
    exit(0);
  }
	
  if(num > 99999) {
    printf("please enter a number between 0 and 100000\n\n");
    exit(0);
  }
	
  tot_dig = 0;
  div = 1;
  n1 = num;
	
  while ( n1 > 9 ) {
    n1 = n1 / 10;
    div = div * 10;
    
    tot_dig++;
  }
  
	
  tot_dig++;
  pos = tot_dig;
	
  while ( num != 0 ) {
    digit = num / div;
    num = num % div;
    div = div / 10;
    switch(pos) {
        case 2:
        case 5: 
				  if ( digit == 1 )
					  flag = 1;
				  else {
            flag = 0;
					  switch(digit) {
						  case 2: printf("twenty ");break;
						  case 3: printf("thirty ");break;
						  case 4: printf("forty ");break;
						  case 5: printf("fifty ");break;
						  case 6: printf("sixty ");break;
						  case 7: printf("seventy ");break;
						  case 8: printf("eighty ");break;
						  case 9: printf("ninty ");
					}
		  }
			break;
   case 1:
   case 4:
      if (flag == 1) {
			  flag = 0;
				switch(digit) {
				  case 0 : printf("ten ");break;
					case 1 : printf("eleven ");break;
					case 2 : printf("twelve ");break;
					case 3 : printf("thirteen ");break;
					case 4 : printf("fourteen ");break;
					case 5 : printf("fifteen ");break;
					case 6 : printf("sixteen ");break;
					case 7 : printf("seventeen ");break;
					case 8 : printf("eighteen ");break;
					case 9 : printf("nineteen ");
			  }
			} else {
			  switch(digit) {
				  case 1 : printf("one ");break;
					case 2 : printf("two ");break;
					case 3 : printf("three ");break;
					case 4 : printf("four ");break;
					case 5 : printf("five ");break;
					case 6 : printf("six ");break;
					case 7 : printf("seven ");break;
					case 8 : printf("eight ");break;
					case 9 : printf("nine ");
			  }
		  }
            
			if (pos == 4) 
			  printf("thousand ");
			break;
				
      case 3:
				if (digit > 0) {
					switch(digit) {
						case 1 : printf("one ");break;
						case 2 : printf("two ");break;
						case 3 : printf("three ");break;
						case 4 : printf("four ");break;
						case 5 : printf("five ");break;
						case 6 : printf("six ");break;
						case 7 : printf("seven ");break;
						case 8 : printf("eight ");break;
						case 9 : printf("nine ");
					}
					printf("hundred ");
				}
        break;
      }
      pos--;
    }
    if (pos == 4 && flag == 0)
		  printf("thousand");
    else if (pos == 4 && flag == 1)
		  printf("ten thousand");
	
    if (pos == 1 && flag == 1)
		  printf("ten ");
}