#include <stdio.h>

#include <math.h>

void write_number(int a, char *s)

{

int h, t;

char *digits[10] = {"zero", "one", "two", "three", "four", "five", "six",

"seven", "eight", "nine"};

char *tens[10] = {"", "", "twenty", "thirty", "fourty", "fifty",

"sixty", "seventy", "eighty", "ninety"};

char *teens[10] = {"ten", "eleven", "twelve", "thirteen", "fourteen",

"fifteen", "sixteen", "seventeen", "eighteen",

"nineteen"};

if (a == 0) return;

h = a / 100;

a -= 100 * h;

t = a / 10;

a -= 10 * t;

if (h > 0) printf("%s hundred ", digits[h]);

if (t > 1) printf("%s ", tens[t]);

else if (t > 0) printf("%s ", teens[a]);

if (t != 1 && a > 0) printf("%s ", digits[a]);

if (*s) printf("%s ", s);

}

void write_cents(double amount)

{

int a;

a = 100 * amount + 0.5;

printf("dollars and ");

if (a != 0) write_number(a, "cents");

else printf("no cents");

putchar('\n');

}

void numtostr(double amount)

{

int n;

char *s[5] = {"", "thousand", "million", "billion", "trillion"};

double base[5] = {1.e0, 1.e3, 1.e6, 1.e9, 1.e12};

if (amount == 0) {

printf("zero\n");

return;

} else if (amount < 0) return;

n = log10(amount) / 3;

while (amount >= 1.0) {

write_number((int)(amount/base[n]), s[n]);

amount = fmod(amount, base[n--]);

}

write_cents(amount);

}

main()

{

double amount;

do {

printf("Input amount $"); scanf("%lf", &amount);

if (amount >= 0) numtostr(amount);

} while (amount > 0.0);

return 0;

}