<s>关于scanf函数%c之前与之后使用空格的问题</s>
<s>你看c标准里对scanf format的说明 Whitespace character: the function will read and ignore any whitespace characters encountered before the next non-whitespace character (whitespace characters include spaces, newline and tab characters -- see isspace).</s><s>A single whitespace in the format string validates any quantity of whitespace characters extracted from the stream (including none).</s><s>如果你是"%c ", 读完所有的字符后，还需要匹配一个" ", 你输入任何空白字符或非空白字符都可以完成匹配.</s><s>但必须有这么一个字符。</s><s>如果是" %c", 第一个" "在碰到你输入的a时就完成匹配了 。</s><s>(参见标准中最后那个including none)</s>
