c中的struct数组

Question

我正在尝试在C中编写一个函数,它从文件中读取一些用逗号分隔的值,每行有4个值,最后一个是整数,我想把它们放在一个分配的空间中.当我试图在while循环中从内存中读取它们时它们很好但是从for循环或从函数外部我只得到文件的最后一行多次,在少数情况下它们会遗漏一些字符.我是C的新手,但我认为它与strtok()功能有关.

这是我的代码:

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

    typedef struct {
        char * foo;
        char * bar;
        char * baz;
        int qux;
    }structure;

    char * readFile(const char * filename, structure * array){
        const int maxstring=100;
        FILE * fr=fopen(filename,"r");
        char * rc;
        char buf[maxstring];
        while(( rc = fgets(buf, maxstring, fr) )) {
            array->foo=strtok (buf,",");
            array->bar=strtok (NULL,",");
            char *aux=strtok (NULL,",");
            array->qux=atol(strtok (buf,","));
            array->baz=strtok(aux,"\n");
            printf("%s,%s,%s,%d\n",array->foo,array->bar,
            array->baz,array->qux);
            array++;
        }
        array=array-9;
        for (int i=0;i<10;i++){
            printf("%s,%s,%s,%d\n",array->foo,array->bar,
            array->baz,array->qux);
            array++;
        }
        return "Success";
    }


    int main(){
        structure * array=malloc(100*sizeof(structure));
        readFile("repository.txt",array);
        free(array);
        return 0;
    }

Answer 1

问题是你存储的返回指针strtok.该函数strtok返回原始缓冲区内存中的指针,即指针内部buf.并且你buf在每次迭代时都会覆盖(通过fgets).

解决问题的最简单方法是strdup返回的值strotk:

char * p = strtok (buf,",");
if (p)
    array->foo = strdup(p);

您存储的其他内容也是如此.free当你完成它们时别忘了打电话.