Thread: Refresh a file

Hello everyone, I might be need your help in a thing that has been bothering me.

I have a function called map() that creates a file called 'merdas.txt' and writes to it.
After that, I call a function called map2() that collects the information inside 'merdas.txt' and separates it in a few files.

Now, this is working, thing is, it only works this way.

I compile the executable 1st time :

'merdas.txt' is created.

I compile the executable 2nd time :

The few files separately are created.

This is my function that separates 'merdas.txt' in a few :

Code:

void map2(){
    FILE* fpp;
    FILE* fppp;
    int i=0;
    int chave;
    int linhas=0;
    size_t len;
    char* fich;
    char valor[MAXSTRING];
    fpp = fopen("merdas.txt","r");
    if (fpp == NULL) { printf("Este ficheiro ainda não existe \n");}
    else {printf("Existe o ficheiro \n");}
    while(fscanf(fpp,"%d  %s",&chave,&valor)!=-1){
        //printf("chave:%d\nvalor:%s\n",chave,valor);
        const char *str = coiso(chave);
        printf("Vou começar a imprimir os nomes \n");
        printf("str: %s\n",str);
        fppp=fopen(str,"a+");
        //printf("criou o ficheiro\n");
        fprintf(fppp,"%s\n",valor);
        ficheiros[chave]=1;
    }
    fclose(fpp);
}

It tells me the file exists so I have no idea why it ain't creating the few files.

Thanks.

I managed to find out that when he reads the file, this file is empty.
Is there any way I can refresh a folder in C?

One thing I notice it that you need to study the documentation for fscanf(), you're not using it correctly. Another thing are you sure the open inside your loop is working correctly? You need to check the return value of the fopen() function.

How is coiso() defined and implemented?

Also if your file doesn't open you really should take some action, like maybe exiting the program.

Jim

Originally Posted by jimblumberg

One thing I notice it that you need to study the documentation for fscanf(), you're not using it correctly. Another thing are you sure the open inside your loop is working correctly? You need to check the return value of the fopen() function.

How is coiso() defined and implemented?

Also if your file doesn't open you really should take some action, like maybe exiting the program.

Jim

Hello Jim, thanks for your reply.

I'm well aware but fscanf is working, as I've mentioned in the first post, it's working and creating the textfiles, it's only doing that when I compile the program the second time.

Coiso() function is also working fine, I'll show how it's implemented though :

Code:

const char *coiso(int chave)


{
    
    static char str[50];
    
    sprintf(str, "%d.txt", chave);
    
    return str;
    
}

My file is opening, I'm only being able to read what's inside when I compile the second time.
I'm guessing that what I've wrote in the map() function is not being wrote quick enough for the map2() to be able to read it ?

Originally Posted by DeanWinchester

My file is opening, I'm only being able to read what's inside when I compile the second time.
I'm guessing that what I've wrote in the map() function is not being wrote quick enough for the map2() to be able to read it ?

Sounds like output buffering. Try calling

Code:

 fflush(fp);

Also make sure you fclose the file when you're done with it, as that'll also flush all the output.

I'm well aware but fscanf is working,

Only if you're extremely lucky. You are invoking undefined behavior in the following fscanf().

Code:

fscanf(fpp,"%d  %s",&chave,&valor)

How do you send the address of a string to a function? Hint: Not the way you're doing it.

Next, you're trying to reuse an open file pointer. Maybe you should close the file and reset any error flags before you try to reuse the file pointer (move the fclose(fppp) inside the loop).

Jim

Originally Posted by smokeyangel

Sounds like output buffering. Try calling

Code:

 fflush(fp);

Also make sure you fclose the file when you're done with it, as that'll also flush all the output.

Thanks buddy, I was missing a fclose().

Thanks a lot!