c - C中的 "%02s"和 "%2s"有什么区别？

Question

我有以下代码:

char temp[32] = "";
sprintf(temp, "%02s", "A");

但它有警告:Warning 566: Inconsistent or redundant format char 's'，然后我将代码更改为:sprintf(temp, "%2s", "A");，警告消失了，有什么区别？

Answer 1

%0 格式表示“0-padding”，但您不能将其与未定义的字符串格式说明符 (s) 结合使用。

参见 the manual page :

0

The value should be zero padded. For d, i, o, u, x, X, a, A, e, E, f, F, g, and G conversions, the converted value is padded on the left with zeros rather than blanks. If the 0 and - flags both appear, the 0 flag is ignored. If a precision is given with a numeric conversion (d, i, o, u, x, and X), the 0 flag is ignored. For other conversions, the behavior is undefined.