如何从一个句子高效地使用C提取的话呢？ [英] How to extract words from a sentence efficiently in C?

问题描述

我需要提取第一，第二和休息的句子分成三个变量的一个有效的功能。

I need an efficient function that extracts first second and rest of the sentence into three variables.

推荐答案

简单的方法：使用的strtok（）或strtok_r率先拿到两个标记，这将在字符串中删除他们，所以字符串本身将是你的，你正在寻找第三个令牌。

Easy way: Use strtok() or strtok_r to get the first two tokens, which will remove them from the string, so the string itself will be your third token you were looking for.

硬办法：自己解析：（

strtok的是在C字符串库，并会产生变异的原始字符串，所以要小心，先复制的字符串，如果它需要保持不变。

Strtok is in the C string library, and will mutate your original string so be careful, copy the string first if it needs to remain intact.

可能的例子：

//#include <string.h>

char input[] ="first second third forth";
char delimiter[] = " ";
char *firstWord, *secondWord, *remainder, *context;

int inputLength = strlen(input);
char *inputCopy = (char*) calloc(inputLength + 1, sizeof(char));
strncpy(inputCopy, input, inputLength);

firstWord = strtok_r (inputCopy, delimiter, &context);
secondWord = strtok_r (NULL, delimiter, &context);
remainder = context;

printf("%s\n", firstWord);
printf("%s\n", secondWord);
printf("%s\n", remainder);

getchar();
free(inputCopy);

这应该只是罚款，并与线程原始字符串未突变。

This should work just fine and be threadsafe with the original string unmutated.

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