如果你确定字符不是大写字母就是小写字母,而没有其他字符的话,倒是能用switch解决#include #include int main(){ char ch; printf("please input a letter:"); ch = getchar(); switch (ch / 91) { case 0:printf("The character is capital!\n"); break; case 1:printf("The character is lowercase letter!\n"); break; default:break; } return 0;}