忘了一个c语言的api

[一个程序员的修炼之路]

函数实现功能：从输入缓冲区读字符，但不取出来

[acdbxzyw]

ungetc();
A character is virtually put back into an input stream at the same position the last character was read and the internal file position indicator is decreased back to that previous position so that this character is returned by the next call to a reading operation on that stream.

char c=getc(stdin);
	ungetc(c,stdin);