exc/k&r/01-a-tutorial-introduction/01-12.c

#include <stdio.h>

#define IN 0
#define OUT 1

void main()
{
    int c, state = OUT;

    while ((c = getchar()) != EOF) {
        if (c == ' ' || c == '\n' || c =='\t') {
            if (state == IN) {
                putchar('\n');
                state = OUT;
            }
            continue;
        }

        putchar(c);
        state = IN;
    }
    if (state == IN)
        putchar('\n');
}