为什么你可以添加一个整数到字符串字面量？ [英] Why can you add an integer to a string literal?

问题描述

我在搞乱，注意到一些奇怪的东西。你实际上可以做a+ 2 ，程序编译正常，但不输出任何内容。但是a+ 32 说数组下标是数组边界。

I was messing around and noticed something strange. You can actually do "a" + 2 and the program compiles fine, but doesn't output anything. However "a" + 32 says array subscript is above array bounds.

推荐答案

a实际上是一个const char []，但它可以不转换为const char * 或到char * ，当你对指针做数学运算时，它像数组下标语法。所以你正在创建一个新的指针，在字符串中更远。有关指针算术的参考可能很有用。如果你得到一个char *引用的文字，它仍然是未定义的修改它（从经验，它可能会崩溃，如果在只读页面，或可能更改所有引用，它使用）。

"a" is actually a const char[], but it can be converted without a cast to a const char* or to a char* and when you do math on pointers it works like array subscript syntax. So you're creating a new pointer which is farther along in the string. This reference on pointer arithmetic might be useful. If you do get a char* reference to the literal, it still is undefined to modify it (from experience it might crash if in read-only page, or might change all references where it is used).

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