write an algorithm to convert numbers in words
Answers
Answer:
/* C program to print a given number in words. The program handles
numbers from 0 to 9999 */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
/* A function that prints given number in words */
void convert_to_words(char *num)
{
int len = strlen(num); // Get number of digits in given number
/* Base cases */
if (len == 0) {
fprintf(stderr, "empty string\n");
return;
}
if (len > 4) {
fprintf(stderr, "Length more than 4 is not supported\n");
return;
}
/* The first string is not used, it is to make
array indexing simple */
char *single_digits[] = { "zero", "one", "two",
"three", "four","five",
"six", "seven", "eight", "nine"};
/* The first string is not used, it is to make
array indexing simple */
char *two_digits[] = {"", "ten", "eleven", "twelve",
"thirteen", "fourteen",
"fifteen", "sixteen",
"seventeen", "eighteen", "nineteen"};
/* The first two string are not used, they are to make
array indexing simple*/
char *tens_multiple[] = {"", "", "twenty", "thirty", "forty", "fifty",
"sixty", "seventy", "eighty", "ninety"};
char *tens_power[] = {"hundred", "thousand"};
/* Used for debugging purpose only */
printf("\n%s: ", num);
/* For single digit number */
if (len == 1) {
printf("%s\n", single_digits[*num - '0']);
return;
}
/* Iterate while num is not '\0' */
while (*num != '\0') {
/* Code path for first 2 digits */
if (len >= 3) {
if (*num -'0' != 0) {
printf("%s ", single_digits[*num - '0']);
printf("%s ", tens_power[len-3]); // here len can be 3 or 4
}
--len;
}
/* Code path for last 2 digits */
else {
/* Need to explicitly handle 10-19. Sum of the two digits is
used as index of "two_digits" array of strings */
if (*num == '1') {
int sum = *num - '0' + *(num + 1)- '0';
printf("%s\n", two_digits[sum]);
return;
}
/* Need to explicitely handle 20 */
else if (*num == '2' && *(num + 1) == '0') {
printf("twenty\n");
return;
}
/* Rest of the two digit numbers i.e., 21 to 99 */
else {
int i = *num - '0';
printf("%s ", i? tens_multiple[i]: "");
++num;
if (*num != '0')
printf("%s ", single_digits[*num - '0']);
}
}
++num;
}
}
/* Driver program to test above function */
int main(void)
{
convert_to_words("9923");
convert_to_words("523");
convert_to_words("89");
convert_to_words("8989");
return 0;