如何在c中标记整行输入?

发布于 2024-11-01 13:46:19 字数 552 浏览 1 评论 0原文

我需要解析 cmd 中的一行,看起来像这样,

"SOME WHITE SPACE" "var_name" "SOME WHITE SPACE" "var_value" "SOME WHITE SPACE"

我用 fgets: 获取整行:

fgets(input_buf,MAX_LINE_LENGTH,stdin);

并尝试像这样标记:

sscanf(input_buf,"%s", var_buff);

sscanf(input_buf+strlen(var_buff),"%s", var_val_buff);

sscanf(input_buf+(strlen(var_buff)+strlen(var_val_buff)+2),"%s", rest_line_buff);

if (strlen(rest_line_buff) == 0)

    printf("error in usage\n");

我没有得到正确的值,因为空格的数量可能会有所不同。我如何标记输入行?

I need to parse a line from cmd that looks like this

"SOME WHITE SPACE" "var_name" "SOME WHITE SPACE" "var_value" "SOME WHITE SPACE"

i take the whole line with fgets:

fgets(input_buf,MAX_LINE_LENGTH,stdin);

and tried to tokenize like this:

sscanf(input_buf,"%s", var_buff);

sscanf(input_buf+strlen(var_buff),"%s", var_val_buff);

sscanf(input_buf+(strlen(var_buff)+strlen(var_val_buff)+2),"%s", rest_line_buff);

if (strlen(rest_line_buff) == 0)

    printf("error in usage\n");

I dont get the right values as the number of white spaces may vary. how can i tokenize the input line?

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评论(4

我偏爱纯白色 2024-11-08 13:46:19

使用strtok,如示例程序所示如下:

#include <stdio.h>
#include <string.h>

int main ()
{
  char sampleInput[] ="foo bar foo1 bar1 foo2 bar2";
  char *token;
  char *whiteSpace = " \t\n\f\r\v";
  int isVariable = 1;

  token = strtok(sampleInput, whiteSpace);
  while (token != NULL)
  {
     if (isVariable) 
        printf("Variable = %s\n", token);
     else 
        printf("Value = %s\n\n", token);
     isVariable = isVariable ? 0 : 1;
     token = strtok(NULL, whiteSpace);
  }
  return 0;
}

输出:

Variable = foo
Value = bar

Variable = foo1
Value = bar1

Variable = foo2
Value = bar2

Use strtok, as shown in the sample program below:

#include <stdio.h>
#include <string.h>

int main ()
{
  char sampleInput[] ="foo bar foo1 bar1 foo2 bar2";
  char *token;
  char *whiteSpace = " \t\n\f\r\v";
  int isVariable = 1;

  token = strtok(sampleInput, whiteSpace);
  while (token != NULL)
  {
     if (isVariable) 
        printf("Variable = %s\n", token);
     else 
        printf("Value = %s\n\n", token);
     isVariable = isVariable ? 0 : 1;
     token = strtok(NULL, whiteSpace);
  }
  return 0;
}

Output:

Variable = foo
Value = bar

Variable = foo1
Value = bar1

Variable = foo2
Value = bar2
凑诗 2024-11-08 13:46:19

scanf 系列中的所有函数默认聚合并跳过多个空格字符:

sscanf(input_buf," %s %s", var_buff, var_val_buf);

我不确定格式字符串中的前导空格是否是绝对必要的,但我确信如果在开头没有实际的空格,则这是正确的事件输入线。

All functions from the scanf family aggregate and skip multiple whitespace characters by default:

sscanf(input_buf," %s %s", var_buff, var_val_buf);

I am not sure the leading whitespace in the format string is strictly necessary, but I am positive that it is correct event if there is no actual whitespace at the beginning of the input line.

灯下孤影 2024-11-08 13:46:19

使用扫描仪生成器:http://en.wikipedia.org/wiki/Lexical_analysis#Lexer_generator 或者,下载分词器库。

Use a scanner generator: http://en.wikipedia.org/wiki/Lexical_analysis#Lexer_generator or, download a tokenizer library.

陌若浮生 2024-11-08 13:46:19

在这里使用 strtok( )strtok_r( ) 似乎很自然。你为什么决定反对?

It seems to natural to use strtok( ) or strtok_r( ) here. Why have you decided against it?

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