c++ - 通过 "\0"而不是 memset() 批量初始化 char 数组

Question

通常由 memset 初始化的字符数组。

我在我的项目代码中发现了由"\0"初始化的char数组。我还编译并检查了，它工作正常。

我的问题是这是批量初始化 char 数组的正确方法吗？

例如:

char a[20]="\0";
printf("%s", a);

Answer 1

是的，这是正确的方法之一。

对于c

引用 C11，第 6.7.9 章

If there are fewer initializers in a brace-enclosed list than there are elements or members of an aggregate, or fewer characters in a string literal used to initialize an array of known size than there are elements in the array, the remainder of the aggregate shall be initialized implicitly the same as objects that have static storage duration.

并且，关于static存储变量的初始化，

If an object that has static or thread storage duration is not initialized explicitly, then:

— if it has pointer type, it is initialized to a null pointer;

— if it has arithmetic type, it is initialized to (positive or unsigned) zero;

— if it is an aggregate, every member is initialized (recursively) according to these rules, and any padding is initialized to zero bits;

— if it is a union, the first named member is initialized (recursively) according to these rules, and any padding is initialized to zero bits;

对于c++

引用 C++17，第 11.6.2 章

If there are fewer initializers than there are array elements, each element not explicitly initialized shall be zero-initialized.

---

所以，在你的情况下，

char a[20]="\0";

尝试将a[0]初始化为'\0'，a[1]初始化为'\0' (对于空终止符)，其余为 0。 FWIW，'\0' 的十进制值为 0，因此在这种情况下，数组中的所有元素都将具有值 0.

一些类似的初始化语句是

char a[20] = "";
char a[20] = {0};
char a[20] = {'\0'};

对于C++，建议in the other answer ，包括所有以前的语法，

char a[20] = {};

也可以。