C语言 在 C 中使用 strtok 使用多个分隔符拆分字符串

Split string with multiple delimiters using strtok in C

提问by nocturne

I have problem with splitting a string. The code below works, but only if between strings are ' ' (spaces). But I need to split strings even if there is any whitespacechar. Is strtok()even necessary?

我在拆分字符串时遇到问题。下面的代码有效，但前提是字符串之间是 ' '（空格）。但即使有任何空白字符，我也需要拆分字符串。是strtok()甚至必要？

char input[1024];
char *string[3];           
int i=0;

fgets(input,1024,stdin)!='
#include <stdio.h>
#include<string.h>

int main(void)
{    
  char input[1024];
  char *string[256];            // 1) 3 is dangerously small,256 can hold a while;-) 
                                // You may want to dynamically allocate the pointers
                                // in a general, robust case. 
  char delimit[]=" \t\r\n\v\f"; // 2) POSIX whitespace characters
  int i = 0, j = 0;

  if(fgets(input, sizeof input, stdin)) // 3) fgets() returns NULL on error.
                                        // 4) Better practice to use sizeof 
                                        //    input rather hard-coding size 
  {                                        
    string[i]=strtok(input,delimit);    // 5) Make use of i to be explicit 
    while(string[i]!=NULL)                    
    {
      printf("string [%d]=%s\n",i,string[i]);
      i++;
      string[i]=strtok(NULL,delimit);
    }

    for (j=0;j<i;j++)
    printf("%s", string[i]);
  }

  return 0;
}
')               //get input
{                                        
  string[0]=strtok(input," ");               //parce first string
  while(string[i]!=NULL)                     //parce others
  {
     printf("string [%d]=%s\n",i,string[i]);
     i++;
     string[i]=strtok(NULL," ");
  }

回答by P.P

A simple example that shows how to use multiple delimiters and potential improvements in your code. See embedded comments for explanation.

一个简单的示例，展示了如何在代码中使用多个分隔符和潜在的改进。有关解释，请参阅嵌入的注释。

Be warned about the general shortcomings of strtok()(from manual):

请注意strtok()（来自手册）的一般缺点：

These functions modify their first argument.

These functions cannot be used on constant strings.

The identity of the delimiting byte is lost.

The strtok()function uses a static buffer while parsing, so it's not thread safe. Use strtok_r()if this matters to you.

这些函数修改它们的第一个参数。

这些函数不能用于常量字符串。

定界字节的标识丢失。

该strtok()函数在解析时使用静态缓冲区，因此它不是线程安全的。使用strtok_r()如果这个问题给您。

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