Couldn't solve 5 seconds data send from 1 file to another.Pls help need.

[mostafij]

// This code write random data into a file and every 5 seconds this //program send 5 seconds data into another file.

#include <HEADER FILES>

FILE *f1,*f2;

int main(int argc, char *argv[])
{
int i,j,m=0,n=0;
char buf[100];

f1 = fopen("//root//Example//output1.data", "wb+");
if(!f1) printf("File cannot open");

f2 = fopen("//root//Example//output2.txt", "wb");
if(!f2) printf("File cannot open");

srand ( time(NULL) );

for(i=1;i<=30;i++)
{
j=rand()%100;
fprintf(f1,"%d %d\n",i,j);
printf("%d %d \n",i,j);
sleep(1);

if(i%5 == 0)
{
fseek(f1,i*2-10, SEEK_SET );
m=fread(buf,2,10,f1);
n=fwrite(buf,2,10,f2);
printf("\nBuffer= %d %d\n",m,n); //Confirm Read and write
}
}
fclose(f2);
fclose(f1);
}


File "output1.data" showing the output:
1 37
2 52
3 16
4 98
6 13 //Don't have Number 5 data.
7 26
8 11
9 92
10 72

For "output2.txt" showing the output:
1 37
2 52
3 16
4 98
3 16 //Again start from line 3.
4 98
6 13
7 26

Question: Here I didn't get actual answer.Can anybody help me?

My expected answer is

For "output1.data" showing the output:
1 37
2 52
3 16
4 98
5 35 [5 th Second, So data will send 1-5 lines to "output2.txt" file]
6 13
7 26
8 11
9 92
10 72 [10 th Second, So data will send 6-10 lines to "output2.txt" file]

For "output2.txt" showing the output:
1 37
2 52
3 16
4 98
5 35
6 13
7 26
8 11
9 92
10 72

NB: This is not my homework.I am trying to solve this problem. 2 weeks always failed.If u have any new idea... please help me.

Thanks
Mostafijur

[RRick]

First of all, please put [ code=c]...[\code] tags around your code.

Your code has several issues.

  f1 = fopen("//root//Example//output1.data", "wb+");

Why are you opening the file as a binary file? The printf statements do not print out binary information. They convert the integer values to ascii.

What's killing you is you are reading and writing to the same file and using fseek to reposition the data. Fseek deals with number of bytes, not number of lines or number of integers. When your output goes from line 9 to line 10, you are adding an extra byte.

9 92
10 72

You also have to deal with the end of line character, too.

Your loop variable starts at 1 instead of 0. This probably accounts for the missing entries in output2.


What to do? The simpliest thing to do is open 3 files. Write output1, read output1, and write output2. Now you don't have to worry about the fseek. You'll have to be careful about flushing output1 between writing and reading it.