having problems with updating records of one file to another file

i am having problems of updating record present in one file and writing them onto another file in the same record format. it will write the input from command line onto incomingr.dat but not collectr.dat.no errors .
the code is as follows

Code:

---

#include<stdio.h>
#include<stdlib.h>
//#include<conio.h>
struct request
{
float percent_seq;
char type_of_request[20];
int request_size;
};

struct collectrequest
{
float percent_seq;
char type_of_request[20];
int request_size;
};
struct request r;
int main()
{
FILE *fp;

fp=fopen("INCOMINGR.DAT","w");
if(fp==NULL)
{
printf("cannot open file");
return 0;
}

printf("\n enter percent_seq,type_of_request and request_size");
scanf("%f%s%d",&r.percent_seq,r.type_of_request,&r.request_size);
fprintf(fp,"%f%s%d\n",r.percent_seq,r.type_of_request,r.request_size);
fflush(stdin);
insertcollectrequest(fp);


fclose(fp);
return 0;
}
int insertcollectrequest(FILE *fp)
{
FILE *fp2;
struct collectrequest cr;
fp2=fopen("COLLECTR.DAT","w+i");
if(fp2==NULL)
{
printf("cannot open file");
return 0;
}
while(fread(&r,sizeof(r),1,fp)==1)
{
fprintf(fp2,"%f%s%d\n",cr.percent_seq,cr.type_of_request,cr.request_size);
}
fclose(fp2);
}

---

If you properly indent your code, it will be more readable, and more people will read it.

"fflush(stdin)" results in undefined behavior according to the C standard, so until you get rid of that it cannot be eliminated as the potential source of your problem. I presume you are using it to get rid of characters left in the stdin stream buffer. There are better ways to deal with this that do not involve invoking undefined behavior.

For example, write a function that reads a line of input into a local char buffer and extracts the data you want from that.

You are reading your fp file in records and trying to write out text... is there some reason you need to do that?

Also you are reading record r but printing to file from record cr ... I'm thinking you should make up your mind :D

Pluse as already noted ... Some from of structured text formatting ... horizontal indentation, vertical white space, etc. is going to make it a lot --a huge lot-- easier to find this kind of stuff in your code. Take a look at how other people indent and separate their code... there's a reason for it.

> fp2=fopen("COLLECTR.DAT","w+i");
What does "i" mode do?

no it was printed by mistake the only w+ is the mode

Quote:

---

Originally Posted by Salem

> fp2=fopen("COLLECTR.DAT","w+i");
What does "i" mode do?

---

Create selfish code?

> no it was printed by mistake the only w+ is the mode
How can you print something by mistake, from doing a copy/paste from your code editor to the forum?

Unless you're telling us this isn't your real code, and that you're just wasting everyone's time :mad:

the actual code is

Code:

---

#include<stdio.h>
#include<stdlib.h>
//#include<conio.h>
/*this structure is for taking a request from command line*/
struct request
{
float percent_seq;
char type_of_request[20];
int request_size;
};
/*this struct is for having that incoming request appended onto it until a condition is reached*/
struct collectrequest
{
float percent_seq;
char type_of_request[20];
int request_size;
};
struct request cr;
int main()
{
FILE *fp;

fp=fopen("INCOMINGR.DAT","w");
if(fp==NULL)
{
printf("cannot open file");
return 0;
}

printf("\n enter percent_seq,type_of_request and request_size");
scanf("%f%s%d",&r.percent_seq,r.type_of_request,&r.request_size);
fprintf(fp,"%f%s%d\n",r.percent_seq,r.type_of_request,r.request_size);
fflush(stdin);
insertcollectrequest(fp);


fclose(fp);
return 0;
}

int insertcollectrequest(FILE *fp)
{
FILE *fp2;
struct collectrequest cr;
fp2=fopen("COLLECTR.DAT","w+");
if(fp2==NULL)
{
printf("cannot open file");
return 0;
}
 while((fscanf(fp,"%f%s%d",&r.percent_seq,r.type_of_request,&r.request_size))!=EOF)
{
fprintf(fp2,"%f%s%d\n",r.percent_seq,r.type_of_request,r.request_size);
}
fclose(fp2);
}

---

i want to read records from file in record format as well as write on to other file in record format.

You keep using a variable called "r", but you don't have one. How are you even compiling this code?

You also don't prototype your function, which means that may only work by the grace of your compiler, plus you haven't gotten rid of fflush(stdin) yet.