如何使用strtok获取token中的token？

Question

我正在尝试从文件的每一行中分离出标记并打印它们。我使用的分隔符是“,”。但是，某些行的最后一个字符串在字符串中有带“,”的标记。怎么得到里面有“,”的整个字符串？

char *buff = (char*)malloc(sizeof(char)*256);
char *tmp;

while (fgets(buff, 256, FILENAME) != NULL) {
    tmp = strtok(buff, ",");
    printf("%s\n",tmp);

    tmp = strtok(NULL, ",");
    printf("%s\n",tmp);

    tmp = strtok(NULL, ",");
    printf("%s\n",tmp);
    
}

输入文件中的行如下所示：

This,is,a
Code,in,"c,language"
rat, mouse, "rat, mouse"

我试图得到这样的输出：

This
is
a
Code
in
c, language
rat
mouse
rat, mouse

Answer 1

因为星期天空闲是进行一些简单编码的好时间，所以这是我在短时间内编写的解析器。它不解析转义序列并且几乎没有错误处理，但可以帮助您入门。

#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>

void parse(FILE *file) {
    int c;
    // keep track if we are in quotes or not
    bool inquote = false;
    // keep track if the field started or not
    bool infield = false;
    
    while ((c = fgetc(file)) != EOF) {

        if (!infield) {
            // ignore leading spaces before fields
            if (c == ' ') continue;
            infield = true;
        }

        switch(c) {
        case '"':
            inquote = !inquote;
            continue;
        case ',':
            // if comma is in quotes, just print it
            if (inquote) break;
            // fallthrough
        case '\n':
            // comma or newline are field separators
            printf("\n");
            infield = false;
            continue;
        }
        // output the character
        printf("%c", c);
    }
}

int main() {
    parse(stdin);
    return 0;
}

it outputs on godbolt:

This
is
a
Code
in
c,language
rat
mouse
rat, mouse

如何使用strtok获取token中的token？

How to use strtok to get tokens within tokens?

c

string

file

strtok