trying to get text from file in function with malloc

[boomtoom]

void main()
{
    int number;
    totalCallsPtr pcall=NULL;       
    getData(&pcall,&number);    
}

void getData(totalCallsPtr* pcall,int* number)//get data from the text file
    { 
        int i,n;

    FILE *f1;
    f1=fopen(INPUT, "r");   
    if (f1==NULL)
        printf("File not open!\n");
    else
    {
        fscanf(f1,"%d",&n);

        *pcall=((totalCallsPtr)malloc(n*sizeof(CALL)));     
    }

    if((*pcall=(totalCallsPtr)malloc(n*sizeof(CALL)))==NULL)
        printf("not enough memory to allocate");

                for(i=0;i<n;i++)
                {

                fscanf(f1,"%d ",&pcall[i]->day);
                fscanf(f1,"%d:%d:%d ",&pcall[i]->startCall.hours,&pcall[i]->startCall.minutes,&pcall[i]->startCall.seconds);
                fscanf(f1,"%d:%d:%d ",&pcall[i]->endCall.hours,&pcall[i]->endCall.minutes,&pcall[i]->endCall.seconds);
                fscanf(f1,"%c",&pcall[i]->type);

                }
                free(*pcall);
                *number=n;
    }

why doesnt it work for me?

[me_ansh]

Firstly, saying things like 'why doesnt it work for me' does not help us understanding your problem, please specify what exactly is the problem..

[boomtoom]

Firstly, saying things like 'why doesnt it work for me' does not help us understanding your problem, please specify what exactly is the problem..

when i complile the prgoram quits with RUN TIME ERROR

[me_ansh]

Ok, though its not clearly mentioned that what exactly is 'totalCallsPtr' but it can be assumed that its a type defined as pointer to some structure..

My first point of concern:

else
{
fscanf(f1,"%d",&n);

*pcall=((totalCallsPtr)malloc(n*sizeof(CALL))); // 1
}

if((*pcall=(totalCallsPtr)malloc(n*sizeof(CALL)))==NULL) // 2
printf("not enough memory to allocate");

You have allocated a chunk of memory on heap in '1' and gave the address to '*pcall' again you allocated chunk of memory on heap in '2' and stored the address in the same '*pcall' which was previously pointing to a memory allocated on heap in '1'....so, in a nutshell u have lost the control over chunk of memory allocated in '1'

My second point of concern:

for(i=0;i<n;i++)
{

fscanf(f1,"%d ",&pcall[i]->day);
fscanf(f1,"%d:%d:%d ",&pcall[i]->startCall.hours,&pcall[i]->startCall.minutes,&pcall[i]->startCall.seconds);
fscanf(f1,"%d:%d:%d ",&pcall[i]->endCall.hours,&pcall[i]->endCall.minutes,&pcall[i]->endCall.seconds);
fscanf(f1,"%c",&pcall[i]->type);

}

When the value of i becomes '1' then 'pcall' means *(pcall+i) ie *(pcall+1) which means a jump to next structure in memory but pcall points to only single structure and the memory to that structure is allocated on heap

[boomtoom]

Ok, though its not clearly mentioned that what exactly is 'totalCallsPtr' but it can be assumed that its a type defined as pointer to some structure..

My first point of concern:

else
{
fscanf(f1,"%d",&n);

*pcall=((totalCallsPtr)malloc(n*sizeof(CALL))); // 1
}

if((*pcall=(totalCallsPtr)malloc(n*sizeof(CALL)))==NULL) // 2
printf("not enough memory to allocate");

You have allocated a chunk of memory on heap in '1' and gave the address to '*pcall' again you allocated chunk of memory on heap in '2' and stored the address in the same '*pcall' which was previously pointing to a memory allocated on heap in '1'....so, in a nutshell u have lost the control over chunk of memory allocated in '1'

My second point of concern:

for(i=0;i<n;i++)
{

fscanf(f1,"%d ",&pcall[i]->day);
fscanf(f1,"%d:%d:%d ",&pcall[i]->startCall.hours,&pcall[i]->startCall.minutes,&pcall[i]->startCall.seconds);
fscanf(f1,"%d:%d:%d ",&pcall[i]->endCall.hours,&pcall[i]->endCall.minutes,&pcall[i]->endCall.seconds);
fscanf(f1,"%c",&pcall[i]->type);

}

When the value of i becomes '1' then 'pcall' means *(pcall+i) ie *(pcall+1) which means a jump to next structure in memory but pcall points to only single structure and the memory to that structure is allocated on heap

#include <stdio.h>
#include <stdlib.h>
#define INPUT "tel.txt"

typedef struct
{
int hours;
int minutes;
int seconds;
} START_TIME ;

typedef struct
{
int hours;
int minutes;
int seconds;
} END_TIME ;

typedef struct
{
int day ;
START_TIME startCall;
END_TIME endCall;
char type;
} CALL ;

typedef CALL* totalCallsPtr;

sorry ..this is the struct.

um im a little bit confused? what i should do then so i could keep the malloc in the function?

[me_ansh]

With reference to my earlier post

1) For 'My first point of concern' just replace the code snippet

else
{
fscanf(f1,"%d",&n);

*pcall=((totalCallsPtr)malloc(n*sizeof(CALL)));
}

if((*pcall=(totalCallsPtr)malloc(n*sizeof(CALL)))==NULL)
printf("not enough memory to allocate");

with

else
{
fscanf(f1,"%d",&n);

if((*pcall=(totalCallsPtr)malloc(n*sizeof(CALL)))==NULL)
printf("not enough memory to allocate");
}

2) For 'My second point of concern', i assume that the file from which you are reading the values contains only a single line so change the following code snippet:

for(i=0;i<n;i++)
{

fscanf(f1,"%d ",&pcall[i]->day);
fscanf(f1,"%d:%d:%d ",&pcall[i]->startCall.hours,&pcall[i]->startCall.minutes,&pcall[i]->startCall.seconds);
fscanf(f1,"%d:%d:%d ",&pcall[i]->endCall.hours,&pcall[i]->endCall.minutes,&pcall[i]->endCall.seconds);
fscanf(f1,"%c",&pcall[i]->type);

}

with

fscanf(f1,"%d ",&pcall->day);
fscanf(f1,"%d:%d:%d ",&pcall->startCall.hours,&pcall->startCall.minutes,&pcall->startCall.seconds);
fscanf(f1,"%d:%d:%d ",&pcall->endCall.hours,&pcall->endCall.minutes,&pcall->endCall.seconds);
fscanf(f1,"%c",&pcall->type);

Hope it helps......

[boomtoom]

it containts 8 lines
or unknown size of lines thats why i used malloc
ummm so what u suggest me to do?

[MosaicFuneral]

Major violations of the CODE TAG rule, that's the problem here.

[me_ansh]

malloc(n*sizeof(CALL))

Sorry i overlooked 'n' in the above line,So, you actually are allocating size to 'n' structures of CALL type. Now, I think you need to post the text file from which you are reading...I hope that is not difficult for you..

[boomtoom]

6
14 18:08:12 18:13:55 g
12 10:00:09 10:03:02 y
16 16:42:30 16:45:29 u
1 10:01:15 13:23:03 u
15 04:03:52 09:11:03 y
14 19:15:44 22:36:54 g

[boomtoom]

hey
i hope yuo didnt forget me :-)
any solution?

[boomtoom]

malloc(n*sizeof(CALL))

Sorry i overlooked 'n' in the above line,So, you actually are allocating size to 'n' structures of CALL type. Now, I think you need to post the text file from which you are reading...I hope that is not difficult for you..

hey
i hope you didnt forget me:)
any solution?

[Murtan]

I wasn't in your original chain...but I'll try to help.

(I ended up compiling and running your code in the debugger)

Your problem is that you have a pointer to a pointer and you're indexing off the wrong pointer.

I changed your code: fscanf(f1,"%d ",&pcall[i]->day); to this code: fscanf(f1,"%d ",&(*pcall)[i].day); (with all of the other lines in that section) and the code no-longer faults.

I also commented out the free(*pcall); as you are returning the array to the caller. Either don't pass pcall to getData and then you can free it, or don't free the data you're returning to the caller.

[me_ansh]

Sorry.i was out of town....hope you got the answer...