c的putchar

n0noper

MSDN说：The return value is EOF for an error or if the end-of-file character or the end-of-string character is encounteredin the first attempt to read a character.
// Ctrl+Z  必须是输入行第一个字符

而撸主输入的Ctrl+z对应输入的ASCII码对应的就是右箭头 (Ctrl+Y就是↓，详情请查看ASCII码表)