7.6 chcount.c -- 使用逻辑与运算符

include <stdio.h>

define PERIOD '.'

int main(void)
{
char ch;
int charcount = 0;
while ((ch = getchar()) != PERIOD)
{
if (ch != '"' && ch != ''')
charcount++;
}
printf("There are %d non-quote characters.\n", charcount);
return 0;
}