Thread: Beginner with C: Problem with textual files

Hello,
I'm trying to write a program for my assignment. I'm using STRUCTS and fprintf for writing in a file. Problem: I have main screen with choices, like, create (text file with student info), append / add - (not yet started working on it), delete student(s) - (not yet started working on it) and list students from certain file - (not yet started working on it). In create, I'm passing a size of STRUCT array to function, and in function, everything works, but I can't seem to implement anything that will check if the file already exists. I'm using fgets for user input for file name and I'd really appreciate if someone could help me around checking problem. I've tried access one, it either gives me "File exists!" all the time, or lets me in loop and then breaks after 1st input (even tho I don't have any break in loop).

Thank you for your time and help, 574515.

STURCT:

Code:

typedef struct date_Of_Birth {
    short int day;
    short int month;
    short int year;
}DATE;

typedef struct student {
    int pin;
    char fname[30];
    char lname[30];
    DATE date;
    float gpa;
}STUDENT;

Code:

void create_List(int size) {

    STUDENT* p_Stu = (STUDENT*)calloc(size, sizeof(STUDENT)); //struct pointer
    if (p_Stu == NULL)
        fail();

    char n_F_Name[200];
    int i, len = strlen(n_F_Name);

    FILE* fCreate;
    fCreate = NULL;

    printf("Enter a name for a file: ");
    fgets(n_F_Name, 200, stdin);

    /*for fail

        printf("File with given name already exists.\n");
        system("pause");
        system("cls");
        choice_Of(1);
        fclose(fCreate);
    for success
        strcat(n_F_Name, ".txt");
        fCreate = fopen(n_F_Name, "w");
        if (fCreate == NULL)
            fail();*/

        for (i = 0; i < size; i++)
//long for loop for input, works without file check

    fclose(fCreate);
    free(p_Stu);
}

Found the solution! Thank you for taking your time and looking here!

Code:

if (fCreate = fopen(e_F_Name, "r") == NULL) {
    printf("File with given name already exists.\n");
    system("pause");
    system("cls");
    choice_Of(1);
    fclose(fCreate);
}
    else {
//does the input

Originally Posted by Salem

Did you get an error message like this when you compiled?

Code:

bar.c:5:11: warning: assignment makes pointer from integer without a cast [-Wint-conversion]
   if ( fp = fopen("foo","r") == NULL) {
           ^

No, I did not. I haven't gotten any errors. I'm using Visual Studio 2019. And I do check for errors and warning messages. The only warning message I got was that types differ, since fopen returns int and I'm checking with FILE* pointer. So, as I said, still a beginner, still not sure how things should or do work. Thank you for your tips.

I've tried changing it and it was as Salem said. Well, I'm still learning, and our courses are going slowly. We haven't had any proper assignments yet, so I'm "winging" it on my own. Thank you for your help!