Thread: Need help with a project

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX 4


struct data {
    char name[20];
    char surename[20];
};
struct student {
    struct data data_s;
    float average;
    int grades[10];
};
int grades_f(struct student* grades_in);


int main(int argc, char* argv[])
{


    struct student students[MAX];
    int counter = 0;
    printf("Name of the first student: ");
    gets(students[counter].data_s.name);
    while (counter < MAX) {
        printf("Student's surename: ");
        gets(students[counter++].data_s.surename);
        if (counter < MAX) {
            printf("Name of the next student: ");
            gets(students[counter].data_s.name);
        }
    }
    grades_f(students);
    system("PAUSE");
    return 0;
}


int grades_f(struct student* grades_in)
{
    int i;
    for (i = 0; i < MAX; i++, grades_in++) {
        printf("Grades of student %d: \n", i + 1);
        scanf("%f", grades_in->grades);
    }
}

Originally Posted by awsdert

reason I asked about the system("pause") is redundant now but I'll say it anyway, not all systems do the same thing the same way or with the same commands hence the check.

If you intended grades_in to be a constant pointer then you're mus-understanding something, const modifier makes the content of a variable constant not the variable itself so in this instance the struct is constant but not the pointer.

I got it already, check post above for my current code, its not const anymore.

Yeah my post came in just a second after yours, are you still getting the issue after removing const?

Originally Posted by awsdert

Yeah my post came in just a second after yours, are you still getting the issue after removing const?

I've got a different issue now, the function works, but I can't enter grades for more than 1 student, after that it's just scrolls down and the program is over.

no ideas right now but for iterators should get in the habit of putting ++ on left side for speed (unless you have good reason to put on right hand side like in your first loop)

Interesting, I thought this program is not sth extremely hard...

sth? dunno what that means but no the program is not hard, just sometimes there are underlying errors in code that programmers don't spot because it's just not obvious enough.

try the msvc compiler, it might shout about something gcc ignores because it is technically correct even if the result is not what is desired.

I think you've done pretty well in the time you allowed yourself. I know C (more so than some other languages) is a massive spew of gobbledegook when you start.

If you still have time, I don't think the last few bits you mnetioned in your original post will be too bad. Printing stuff out is much either than reading stuff in. If you have any specific questions I'm sure we'll be happy to help.

So I compiled your code with -Wall (GCC) and it did kick off pretty hard about you using gets(). Please don't use gets() -- use fgets() -- it is safer and good practice.

Apart from the massive hissy fit about gets(), there were a couple of warnings you may with to do something about:

test.c:48:1: warning: control reaches end of non-void function [-Wreturn-type]

It's not the end of the world, but better to use void if you don't intend to return a value.

This one was more worrying:

test.c:46:9: warning: format ‘%f’ expects argument of type ‘float *’, but argument 2 has type ‘int *’ [-Wformat=]
scanf("%f", grades_in->grades);

This will *not* end well!! When you come to try to print those ints, you'll not get what you were expecting. Nor if you try to print them as floats. There are lots of good references for the various printf specifiers (e.g. printf - C++ Reference) but really I only used %d (signed integer) for the first few years of using C.

Oh, the only other thing. I'd recommend against using system(pause). It's more of a personal thing than anything I can strongly back up technically -- true, it only works in Windows but there's a pile of stuff that only works on Linux or other OSs. I guess I have a moral problem with it because it's so commonly taught to beginners (along with a few other Windowsisms) without a proper discussion of it being OS specific.

Good luck with your project

I didn't even know that was a msw command, then again I never use the cmdline for doing anything other than viewing data anyway.