Thread: Getting an error message!

Hey,

Code:

/*
 *Database for storing music cd.
 */

#include<stdio.h>

#define MAX      200 //max characters a user can enter

/*prototypes*/
void write_record(void);
int file_exists(void);
void file_new(void);
void file_open(void);

/*structure for music cd*/
typedef struct cd
{
        char   title[MAX];
        char   artist[MAX];
        int    tracks;
        int    album;
        float   price;
        
        struct cd  *next;
}cd;

/* Global Variables: */ 
cd    *head = NULL; // a pointer that points to start of the cd node.
cd    *curr;         // pointer that point to current cd node
int   changes = 0;  // boolean: if changes made or not
char  fname[MAX];   // stores a name of a file.

/*function that shows up on exit*/
void quit(void)
{
     printf("\nThank you for using database\n");
     system("pause");
}


/*Function to see if a file exists*/
int file_exists(void)
{
    FILE *fptr = fopen(fname,"rb"); //open a file for reading.
    
    if(fptr == NULL)              //if file does not exists return 0.
        return 1;
    else                          //if file exists:
    {
        fclose(fptr);             //close file
        return 0;                 //return 1.
    }
}

int main(void)
{
    int  choice;         //variable that will store choice which the user enters
    void (*funcPtr)(void); //a pointer to a function that takes no arguments nor returns anything
    
    atexit(quit); //calls 'quit' function b4 program exits
    
    /*Loop that will only break on exit*/
    for(;;)
    {      
           printf("\nCurrent file open: %s\n",fname); // print current file opened
           
           /*print menu*/
           puts("\nMenu: \n");
           puts("     1. File new");
           puts("     2. File open");
           puts("     3. Write a record");
           puts("     4. Delete a record by number");
           puts("     5. Delete a record by title");
           puts("     6. Save records");
           puts("     7. Save records with a new file name");
           puts("     8. Edit a record");
           puts("     9. Delete a file");
           puts("    10. Exit");
           
           scanf(" %d",&choice); //ask user for choice
           
           switch(choice)
           {
                case 2:
                     file_open();
                     break;
                case 10:
                     exit(0);
                     break;
           }
    }
}
     
void file_open(void)
{
     /*check if there are changes and then see if a the user wants to discard the records*/
     if(changes && yesno("Are you sure you want to discard the records?"))
     {
         return;
     }
     
     /*ask the user the file name they would like to open*/
     printf("Enter the file name you would like to open: ");
     scanf (" %s",fname);
     
     /*check if the file exists*/
     if(file_exists == 1)
     {
         printf("File does not exists!\n");
         fname[0] = '\0';
         return;
     }
}

I have shorten my code, so that is doesn't consumes much time.

Why is it giving me an error saying "comparison between a pointer and integer" when I am doing "if(file_exists == 1)" ?

And its not working.

Originally Posted by novacain

Because you forgot the brackets, so the compiler thinks you ment a pointer to the 'file_exists' function.

if(file_exists == 1) should be if(file_exists() == 1)

BTW why your comments in the file_exists function are very misleading...

and the file name should not be a global, you should pass the file name into the file_exists function as a param.

Ow, didn't even notice that mistake. Thanks man, and I will try and make the comments more useful. And fname is global because many functions are using it.

Originally Posted by Salem

You barely need one hand to count the number of functions you have.

Did I mention I have shorten the program? Give me another reason to when to use global variables.