Thread: Sequential File Reading Error:

While you're at it, read this FAQ entry on why you don't want to do this:

Code:

while (!feof(cfPtr)){

Quzah.

Originally Posted by Maragato

Thx a lot, well I'm having huge problems using () and {}, specially {} in C, I never know exactly when I should open a {} block, even have been reading about it it seems each style of programming has different options for when using {}.

You use a braces block { } whenever you want to wrap a few statements together for execution. The most common of these are inside loops, after if statements (and else), and in case statements.
Here is an example:

Code:

if( a == b )
    printf("This statement executes if a == b.\n");
printf("This always executes.\n");

Now, if we wanted them both to execute if a == b, we'd wrap them in braces:

Code:

if( a == b )
{
    printf("This statement executes if a == b.\n");
    printf("This does too now.\n");
}

Think of each { as saying "Start a group of statements.", and } as "Stop a group of statements.". The same pair is used for for, while and do while loops. Also in switch statements and the like

You can use them elsewhere, but for now, stick with the basic use of them.

They're also used in defining structures and unions (and classes in C++), as well as to contain the body of functions, array initializations, and such.

Parenthesis are used in function calls, definitions, and declarations, as well as in if statements, loops, etc. Another use is as you'd use them in math, to wrap items in parenthesis for determining order of evaluation.

There's more to it than that, but I'd suggest looking into a good C book for more, as this post would turn into a book were I to show you every example of the usage of both.

Quzah.

I already showed you how to read a file here
http://cboard.cprogramming.com/showthread.php?t=55688

So why have yet another go at inventing something different (and still non-functional)

Code:

#include<stdio.h>

void do_write ( void ) {
    char buff[BUFSIZ];
    int account;
    char name[30];
    float money;
    FILE *cfPtr;

    if ((cfPtr = fopen("client.dat", "w")) == NULL)
        printf("Unable to open the file");
    else {
        printf("Give an account number, a name and the amount of money\n");
        printf("Give EOF to stop\n");

        while (fgets(buff, BUFSIZ, stdin) != NULL) {
            if (sscanf(buff, "%d%s%f", &account, name, &money) == 3) {
                fprintf(cfPtr, "%d %s %.2f\n", account, name, money);
            } else
                printf("ERROR!");
        }
        fclose(cfPtr);
    }
}

void do_read ( void ) {
    char buff[BUFSIZ];
    int account;
    char name[30];
    float money;
    FILE *cfPtr;

    if ((cfPtr = fopen("client.dat", "r")) == NULL)
        printf("Unable to open the file");
    else {
        while (fgets(buff, BUFSIZ, cfPtr) != NULL) {
            if (sscanf(buff, "%d%s%f", &account, name, &money) == 3) {
                fprintf(stdout, "%-10d%-13s%7.2f\n", account, name, money);
            } else
                printf("ERROR!");
        }
        fclose(cfPtr);
    }
}


int main ( void ) {
    do_write();
    do_read();
    return 0;
}

Look how similar the writing and reading functions are.
With a little bit of effort, you could probably pass a few parameters to a single common function.

> But the first post was to WRITE in the file the second was to READ
One reads from stdin and writes to a file
One reads from a file and writes to stdout
It's all copying information from one FILE* to another FILE*