K&R2 Exercise 1-20

1-20.c

#include <stdio.h>

#define TABSTOP 8

int mod(float, float);

int main()
{
	int c, i, cc;

	cc = 0;
	while((c = getchar()) != EOF){
		if(c != '\t'){
			if(c == '\n')
				cc = -1;
			putchar(c);
			++cc;
		}
		else{
			do
				putchar(' ');
			while(mod(++cc, TABSTOP) != 0);
		}
	}
}

int mod(float dividend, float divisor)
{
	int division;
	division = dividend/divisor;
	return dividend - (division * divisor);
}