#include <stdio.h> int main() { char letter = 0; while (scanf("%c", &letter) != EOF) { getchar();//吃掉上次输入后的回车 if ( (letter >= 65 && letter <= 90)|| (letter >= 65 + 32 && letter <= 90 + 32) ) { printf("%C is an alphabet.\n", letter); } else { printf("%C is not an alphabet.\n", letter); } } return 0; }