Unknown problem

Mindphuck · 04-08-2006, 02:25 PM

Okay, here's the code:

Code:

#include <stdio.h>
#include <string.h>

void add(char **data, int rows);
void del(char **data, int rows);
void display(char **data, int rows);
void save(char **data, int rows, FILE * fp);
void menu();

int main()
{
    int x;
    int q;
    int quit;
    char **data;
    FILE * fp = fopen("list.dat", "r+");
    if(fp == NULL)
    {
          fp = fopen("list.dat", "w+");
    }
    for(x=0;fgets(data[x], 1000, fp) != NULL;x++);
    {
                          fgets(data[x], 1000, fp);
    }
    while(quit != 1){
    menu();
    scanf("%d", q);
    switch(q)
    {
                case 1:{
                     add(data, x);
                     save(data, x, fp);
                     }
                case 2:{
                     del(data, x);
                     save(data, x, fp);
                     }
                case 3:{
                     display(data, x);
                     }
                case 4:{
                     quit = 1;
                     }
    }
}
fclose(fp);
return(0);
}                     
      
void add(char **data, int rows){
     char *add;
     printf("Please enter string to be added to the data file: ");
     scanf("%s", *add);
     strcat(add, "\n");
     strcpy(data[rows+1], add);
     }
     
void del(char **data, int rows){
     int del;
     display(data, rows);
     printf("Please enter the number of the entry to be deleted: ");
     scanf("%d", del);
     data[del]= "";
     }

void display(char **data, int rows){
     int i;
     for(i=0;i<=rows;i++){
     printf("[%d]\t%s\n",i,data[i]);
     }
     }
     
void save(char **data, int rows, FILE * fp){
     int i;
     for(i=0;i<=rows; i++){
                      strcat(data[i], "\n");
                      fputs(data[i], fp);
                      }
     }

void menu(){
     printf("Welcome to the menu.\n");
     printf("1) Add data to the file.\n");
     printf("2) Remove data from the file.\n");
     printf("3) Display contents of the file.\n");
     printf("4) Exit the program.\n");
     printf("Please insert the corresponding number for the function you wish to perform: ");
     }

On compile it has no errors - but when I run it, it crashes before it displays the menu (menu()

. I'm not sure why, do any of you have any ideas? Also, feel free to tell me where my code is inefficient

Tonto · 04-08-2006, 02:28 PM

Code:

    for(x=0;fgets(data[x], 1000, fp) != NULL;x++);
    {
                          fgets(data[x], 1000, fp);
    }

Can you see it now? Also

Code:

    FILE * fp = fopen("list.dat", "r+");
    if(fp == NULL)
    {
          fp = fopen("list.dat", "w+");
    }

That's kind of silly. Edit: And finally, scanf accepts a pointer

Code:

scanf("%d", q);
scanf("%d", &q);

Mindphuck · 04-08-2006, 02:31 PM

Quote:

Originally Posted by Tonto

Code:

    for(x=0;fgets(data[x], 1000, fp) != NULL;x++);
    {
                          fgets(data[x], 1000, fp);
    }

Can you see it now? Also

Code:

    FILE * fp = fopen("list.dat", "r+");
    if(fp == NULL)
    {
          fp = fopen("list.dat", "w+");
    }

That's kind of silly. Edit: And finally, scanf accepts a pointer

Code:

scanf("%d", q);
scanf("%d", &q);

I was told to do the for loop like that by a friend after my code didn't work the first time. What's wrong with the fopen part? And finally, oops at forgetting the &

ortegac · 04-08-2006, 02:35 PM

Code:

--------------------Configuration: ass5pract - Win32 Debug--------------------
Compiling...
ass5pract.c
C:\Documents and Settings\Famili@\My Documents\aaron\CM22\ass5pract.c(21) : warning C4700: local variable 'data' used without having been initialized
C:\Documents and Settings\Famili@\My Documents\aaron\CM22\ass5pract.c(27) : warning C4700: local variable 'q' used without having been initialized
C:\Documents and Settings\Famili@\My Documents\aaron\CM22\ass5pract.c(53) : warning C4700: local variable 'add' used without having been initialized
C:\Documents and Settings\Famili@\My Documents\aaron\CM22\ass5pract.c(62) : warning C4700: local variable 'del' used without having been initialized

ass5pract.obj - 0 error(s), 4 warning(s)

You get 4 warnings they are not intialized, dont you think that is messing it up?

Also try to only one with one function at a time. Examples use only the funtion to display, try too break your program in smaller parts. To see where the error is?
Then if you see the display funtions works, add another one an so on.

Caleb

04-08-2006, 02:28 PM	#2
Tonto Registered User Join Date: Jun 2005 Location: New York Posts: 1,465	Code: for(x=0;fgets(data[x], 1000, fp) != NULL;x++); { fgets(data[x], 1000, fp); } Can you see it now? Also Code: FILE * fp = fopen("list.dat", "r+"); if(fp == NULL) { fp = fopen("list.dat", "w+"); } That's kind of silly. Edit: And finally, scanf accepts a pointer Code: scanf("%d", q); scanf("%d", &q);
Tonto is offline

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
A question related to strcmp	meili100	C++ Programming	6	07-07-2007 02:51 PM
WS_POPUP, continuation of old problem	blurrymadness	Windows Programming	1	04-20-2007 06:54 PM
Laptop Problem	Boomba	Tech Board	1	03-07-2006 06:24 PM
Unknown problem	pink_langouste	Windows Programming	2	12-04-2002 12:36 AM
beginner problem	The_Nymph	C Programming	4	03-05-2002 05:46 PM