将列表写入（txt）文件

Question

I made a function which turns the random boxes(/nodes/links) of a list into an array (consecutive-memory). All of this because I am trying to fwrite this list into a file(.txt) .

But all that I see when I open the file is the words from the value field and then 39 spaces either blank or with a random character or whatever else. Can someone tell me why this happens?

How can I get the result, either only the value field of each array element ( list link) or all 3 but by calling fwrite once?

struct box {
    char value[20] ;
    struct box * next ; 
    int occurs;
} ;

typedef struct box Box;
typedef Box * List;


Box* list_toarray(List mylist){
    List iter=mylist;
    Box *packed;
    Box *dup;
    dup=packed=malloc((sizeof(Box))*lenlist(mylist));
    while(iter!=NULL){
        memcpy(packed,iter,sizeof(Box));
        packed++;//packed[1];
        iter=iter->next;
        if(iter!=NULL)
            (packed-1)->next=packed;
        else
            (packed-1)->next=NULL;
    }
    printf("\nInput list to array(Consecutive blocks of memory) :\n");
    report(dup);
    return dup;
}

void fread_fwrite_lsttoarray(Box *dup){
    FILE *myfile;
    myfile=fopen("fwfr.txt","wt");
    fwrite(dup,sizeof(Box),6,myfile);
    fclose(myfile);
}

Also this is how I call the function :

fread_fwrite_lsttoarray(list_toarray(newlistasc));

where newlistasc is a random list with struct box elements

Answer 1

in function fread_fwrite_lsttoarray()

change

fwrite(dup,sizeof(Box),6,myfile);

to

fprintf(myfile, "%s, %d\n", dup->value, dup->occurs);

Do not write elememt next into file, because it's value is meanless outside memory.