在C++中实现strtok()函数

strtok()函数是C++中最常用的函数之一。使用分隔符作为指导，该函数可以将文本分割成较小的块或标记。由于strtok()函数的存在，使用字符串在C++中变得简单。本文将对strtok()函数进行详细的讲解，包括其定义、语法、算法和各种实现策略。需要记住的是，strtok函数有一些限制和潜在的缺点。例如，它不能用于const或只读字符串，因为它会直接改变原始字符串。边缘情况和意外输入，如空字符串或在序列中重复出现的分隔符，也可能难以处理。

尽管存在这些缺点，但这个函数仍然是许多程序员的有用工具，并且经常被广泛应用于各种应用程序中，包括文本处理、数据解析和网络协议。它是一个灵活而强大的函数，可以显著简化许多常规编程任务。

Characteristics of strtok() function

To split a string into smaller chunks or tokens based on a delimiter, use the strtok() function in C++. A pointer to the string that has to be tokenized and a string with the delimiter characters are the two inputs for the function. A pointer to the string's very first token is returned by the function. As long as there are tokens left in the string, successive calls to the function with the same string parameter will return additional tokens and this happens with the help of NULL pointer in while loop. When calling the'strtok()' function again, supplying NULL as the first argument instructs the function to pick up where it left off with the previous tokenization of the same string.

When the function'strtok()' is first called with the input string as the first argument, it starts looking for the first token in the string at the beginning. When it locates the initial token, it terminates it by replacing the delimiter that comes after it with the null character (''0''). When'strtok()' is used again with a NULL pointer as the first argument, the function picks up where it left off with the previous tokenization of the string, that is, directly after the previous token. It keeps looking for the delimiter's next appearance.

语法

Char* strtok(char* str, const char* delimiters); 登录后复制