NumberReader.c

/*
 * NumberReader.c
 *
 *  Created on: May 5, 2009
 *      Author: Asela
 *
 *      shows the way to read integers for integer values
 *      ( form INT_MIN+1 to INT_MAX )
 */
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

#define  MILLION 1000000
#define  BILLION 1000000000


void readNumberOneTo_9(int number);
void readNumberOneTo_99(int number);
void readNumberOneTo_999(int number);
void readNumberOneTo_999999(int number);
void readNumberOneTo_999999999(int number);
void readNumberOneTo_999999999999(int number);

void readSecondPlace(int number);
void readNumberEleveToNineTeen(int number);
void readNumberTenToNinTeen(int number);

int main(int argc , char *argv[] ){

 int number;
 printf("Enter the number you want to read : \n");
 scanf ("%d", &amp;number);

 printf("The way to read %d is :   ", number );

 //if number is negative put the word negative the the
 //display and make it positive and read it as a positive
 //value
 if( number &lt; 0){
  printf("Negative ");
  number *= -1;
 }

 if (number == 0 ) {
  printf("Zero");
 }else if (number &lt; 1000 ) {
  readNumberOneTo_999(number);
 }else if (number &lt; MILLION ){
  readNumberOneTo_999999(number);
 }else if (number &lt; BILLION ){
  readNumberOneTo_999999999(number);
 }else if (number &lt;= INT_MAX ){
  readNumberOneTo_999999999999(number);
 }


 return 0;
}

//prints the value of a single number 1 to 9
void readNumberOneTo_9(int number){

 if(number == 1){
  printf("One");
 } else if(number == 2){
  printf("Two");
 }else if(number == 3){
  printf("Three");
 }else if(number == 4){
  printf("Four");
 }else if(number == 5){
  printf("Five");
 }else if(number == 6){
  printf("Six");
 }else if(number == 7){
  printf("Seven");
 }else if(number == 8){
  printf("Eight");
 }else if(number == 9){
  printf("Nine");
 }
}

/*
 * prints values of ten to 19
 * this a special case 'case these
 * numbers have different way of reading
 */
void readNumberEleveToNineTeen(int number){

 if(number == 10){
  printf("Ten ");
 }else if(number == 11){
  printf("Eleven ");
 }else if(number == 12){
  printf("Twelve ");
 }else {
  if(number == 13){
   printf("Thir");
  }else if(number == 15){
   printf("Fif");
  }else {
   readNumberOneTo_9( number % 10 );
  }

  printf("teen");
 }
}

//reads numbers between one and 99
void readNumberOneTo_99(int number){

 if (number &lt; 10){
  readNumberOneTo_9(number);
 } else if (number &lt; 20) {
  readNumberEleveToNineTeen(number);
 }else {

  readSecondPlace( number / 10 );

  if( number % 10 != 0 ){
   readNumberOneTo_9( number % 10 );
  }
 }

}

//reads digit in the second position
// that are multiples of  10
void readSecondPlace(int number ){
 if(number == 2){
  printf("Twen");
 }else if(number == 3){
  printf("Thir");
 }else if(number == 5){
  printf("Fif");
 }else if(number == 8){
  printf("Eigh");
 }else {

  readNumberOneTo_9(number);
 }
 printf("ty ");
}

//reads numbers between one and 099
void readNumberOneTo_999(int number){

 if (number &lt; 10){
  readNumberOneTo_9(number);
 } else if (number &lt; 100) {
  readNumberOneTo_99(number);
 }else {
  readNumberOneTo_9( number/100 );
  printf(" Hundred");

  if( number % 100 != 0){
   printf(" and ");
   readNumberOneTo_99(number % 100);
  }
 }
}

//for numbers greater that 1000
//They have a systematic way of reading
//Numbers read as blocs of three digits
void readNumberOneTo_999999(int number){
 readNumberOneTo_999(number / 1000 );
 printf(" Thousand ");
 readNumberOneTo_999(number % 1000 );
}

void readNumberOneTo_999999999(int number){
 readNumberOneTo_999(number / MILLION );
 printf(" Million ");
 readNumberOneTo_999999(number % MILLION );
}

void readNumberOneTo_999999999999(int number){
 readNumberOneTo_999(number / BILLION );
 printf(" Billion ");
 readNumberOneTo_999999999(number % BILLION );
}