如何检查 char* 变量是否指向空字符串? [英] How can I check if char* variable points to empty string?

问题描述

如何检查 char* 变量是否指向空字符串?

How can I check if char* variable points to an empty string?

推荐答案

检查第一个字符是否为''.您还应该检查您的指针是否为 NULL.

Check if the first character is ''. You should also probably check if your pointer is NULL.

char *c = "";
if ((c != NULL) && (c[0] == '')) {
   printf("c is empty
");
}

您可以将这两个检查放在一个函数中，以使其方便且易于重用.

You could put both of those checks in a function to make it convenient and easy to reuse.

在 if 语句中可以这样理解，如果 c 不为零且字符数组 'c' 的第一个字符不是 '' 或零，则...".

In the if statement can be read like this, "If c is not zero and the first character of character array 'c' is not '' or zero, then...".

&& 只是简单地结合了这两个条件.基本上就是这样说的:

The && simply combines the two conditions. It is basically like saying this:

if (c != NULL) { /* AND (or &&) */
    if (c[0] == '') {
        printf("c is empty
");
    }
}

如果您不清楚这一点，您可能希望获得一本好的 C 编程书籍.我可以推荐一本名为《The C Programming Language》的书.

You may want to get a good C programming book if that is not clear to you. I could recommend a book called "The C Programming Language".

与上述等效的最短版本是:

The shortest version equivalent to the above would be:

if (c && !c[0]) {
  printf("c is empty
");
}

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