练习 1-12 编写一个程序，以每行一个单词的形式打印其输入。

#include <stdio.h>

#define IN 1
#define OUT 0

int main(int argc, char const *argv[])
{
    int c, state;

    state = OUT;

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

    return 0;
}