ex.10.14.c

#include <stdio.h>

int absValue (int intValue)
{
	if ( intValue < 0 ) {
		intValue *= -1;
	}

	return intValue;
}

void intToStr (int intValue, char intString[])
{
	int magnitude = absValue(intValue), sign, i;

	if ( intValue < 0 ) {
		sign = -1;
		i    = 1;
		intString[0] = '-';
	} else {
		sign = 1;
		i    = 0;
	}

	while ( magnitude / 10 > 0 ) {
		++i;
		magnitude /= 10;
	}

	intString[i + 1] = '\0';

	magnitude = absValue(intValue);
	for ( int n = (sign < 0) ? 1 : 0; i >= n; --i ) {
		intString[i] = (magnitude % 10) + '0';
		magnitude /= 10;
	}
}

int main (void)
{
	char intString[20] = { '\0' };

	for ( int intValue = 321; intValue > -321; intValue -= 87 ) {
		printf ("%i\n", intValue);
		intToStr (intValue, intString);
		printf ("\"%s\"\n\n", intString);
	}

	return 0;
}