K&R-1-20.c

#include <stdio.h>

#define COLUMNS 4

int main() {
	int c, counter;

	counter = 0;
	while((c = getchar()) != EOF) {
		if(c != '\t') {
			putchar(c);	
			counter++;	
		}


		if(counter == COLUMNS) counter = 0;


		if (c == '\t') {
			for(int i = 0; i < COLUMNS - (counter % COLUMNS); i++) {
				putchar(' ');
		}
			counter = 0;
		}
		
		if( c == '\n') counter = 0;
	}
}