/* Exercise 3.6 from "The C programming language" book by K&R */

#include <conio.h>
#include <string.h>

void reverse(char s[])
{
	int c, i, j;
	for (i = 0, j = strlen(s)-1; i < j; i++, j--) {
		c = s[i];
		s[i] = s[j];
		s[j] = c;
	}
}

/* converts n to string s[], l - minimal field width */
void itoa(char n, char s[], char l)
{
	int i, sign;
	
	if((sign = n) < 0)
		n = -n;
	i = 0;
	do {
		s[i++] = n % 10 + '0';
	} while ((n /= 10) > 0);
	if (sign < 0)
		s[i++] = '-';
	while (i < l)
		s[i++] = ' ';
	s[i] = '\0';
	reverse(s);
}

int main(void)
{
	char s[100] = "";
	itoa(-123,s,10);
	printf("%s\n",s);
	return 0;
}