如果（A [++] =='X'）本身是C.它细然而，语义不同：您原来的code仅增加 I 如果条件为真，而如果（A [++] == 'X'）总是增加 I 。

if (a[i++] == 'x') by itself is fine in C. It is, however, semantically different: Your original code only increments i if the condition is true, whereas if (a[i++] == 'x') always increments i.