通过使用strsep拆分来解析CSV文件

Question

I'm getting some unwanted output when attempting to parse a comma seperated value file with strsep(). It seems be be working for half of the file, with a number with only one value (ie. 0-9), but as soon as multiple values are added like for instance 512,

It will print 512 12 2 512 12 2 and so on. I'm not exactly sure if this is due to the particular style that I'm looping? Not really sure.

int main() {

        char line[1024];

        FILE *fp;

        int data[10][10];

        int i = 0;
        int j = 0;

        fp = fopen("file.csv", "r");

        while(fgets(line, 1024, fp)) {

                char* tmp = strdup(line);
                char* token;
                char* idx;

                while((token = strsep(&tmp, ","))) {

                        for (idx=token; *idx; idx++) {
                                data[i][j] = atoi(idx);
                                j++;
                        }
                }
                i++;
                j=0;

                free(tmp);

        }


         for(i = 0; i < 10; i++) {

                for(j = 0; j < 10; j++) {
                printf("%d ", data[i][j]);
                }
                printf("\n");
        }

        fclose(fp);
}

Answer 1

It is because you are creating elements by using every characters in the token returned by strsep() as start via the loop

for (idx=token; *idx; idx++) {
        data[i][j] = atoi(idx);
        j++;
}

Stop doing that and create just one element from one token to correct:

while((token = strsep(&tmp, ","))) {

        data[i][j] = atoi(token);
        j++;
}

Also free(tmp); will do nothing because tmp will be set to NULL by strsep() . To free the buffer allocated via strdup() , keep the pointer in another variable and use it for freeing.