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# 1  
Old 03-13-2008
Need help with ftell() function ..
Hello friends,

I need help with ftell function in my programme, I can't figure out why I am not getting the file position what I supposed to get

Here is my code
Code:
void read_line(void *fh, double *input_re, double *input_im){
 
        double a, b;
        char s[50];
        int n;
        int i=0;
 
        if ( fgets(s, sizeof(s), fh) != NULL){
          
          i= ftello(fh);
       }
          printf("FILE Current Pos: %d\n ", i);
           printf("IMP: %s ", s);
          sscanf(s,"%lf %lf",&a,&b);
          
          *input_re = a;
          *input_im = b;
        }
        else{
                rewind(fh);
        }
}

I am calling the above function to read line from a file, assume that the file pointer is always in open mode to read from that file.

But My output is strange . The below is the begining of my output . but not the end..
Code:
 FILE Current Pos: 20
 IMP:  0.137667 0.0595724
 FILE Current Pos: 39
 IMP:  0.102683 0.109343
 FILE Current Pos: 59
 IMP:  0.0508147 0.141131
 FILE Current Pos: 81
 IMP:  -0.00941674 0.149706
 FILE Current Pos: 102
 IMP:  -0.0681001 0.133655
 FILE Current Pos: 121
 IMP:  -0.115576 0.09561
 FILE Current Pos: 142
 IMP:  -0.144043 0.0418468
 FILE Current Pos: 164
 IMP:  -0.148821 -0.0187982
 FILE Current Pos: 186
 IMP:  -0.129114 -0.0763566
 FILE Current Pos: 208
 IMP:  -0.0881689 -0.121354
 FILE Current Pos: 228
 IMP:  -0.03272 -0.146388
 FILE Current Pos: 249
 IMP:  0.0281091 -0.147345

While the first data is matching with the first line of my input file, but the Current position seems to be 20 , which should be 1 in my case. then next position should be 2 , but as I shown the next one is 39.

Please help me what to do to work the ftell() correctly..

My input file is
Code:
0.137667 0.0595724
 0.102683 0.109343
 0.0508147 0.141131
 -0.00941674 0.149706
 -0.0681001 0.133655
 -0.115576 0.09561
 -0.144043 0.0418468
 -0.148821 -0.0187982
 -0.129114 -0.0763566
 -0.0881689 -0.121354
 -0.03272 -0.146388
 0.0281091 -0.147345

I also tried with
Code:
 long i=0;
 i= ftello(fh);

But no change..

Regards,
user_prady
Last edited by user_prady; 03-13-2008 at 05:02 AM..
# 2  
Old 03-13-2008
Data
Quote:
Originally Posted by user_prady
Hello friends,

I need help with ftell function in my programme, I can't figure out why I am not getting the file position what I supposed to get

Here is my code
Code:
void read_line(void *fh, double *input_re, double *input_im){
 
        double a, b;
        char s[50];
        int n;
        int i=0;
 
        if ( fgets(s, sizeof(s), fh) != NULL){
          
          i= ftello(fh);
       }
          printf("FILE Current Pos: %d\n ", i);
           printf("IMP: %s ", s);
          sscanf(s,"%lf %lf",&a,&b);
          
          *input_re = a;
          *input_im = b;
        }
        else{
                rewind(fh);
        }
}

I am calling the above function to read line from a file, assume that the file pointer is always in open mode to read from that file.

But My output is strange . The below is the begining of my output . but not the end..
Code:
 FILE Current Pos: 20
 IMP:  0.137667 0.0595724
 FILE Current Pos: 39
 IMP:  0.102683 0.109343
 FILE Current Pos: 59
 IMP:  0.0508147 0.141131
 FILE Current Pos: 81
 IMP:  -0.00941674 0.149706
 FILE Current Pos: 102
 IMP:  -0.0681001 0.133655
 FILE Current Pos: 121
 IMP:  -0.115576 0.09561
 FILE Current Pos: 142
 IMP:  -0.144043 0.0418468
 FILE Current Pos: 164
 IMP:  -0.148821 -0.0187982
 FILE Current Pos: 186
 IMP:  -0.129114 -0.0763566
 FILE Current Pos: 208
 IMP:  -0.0881689 -0.121354
 FILE Current Pos: 228
 IMP:  -0.03272 -0.146388
 FILE Current Pos: 249
 IMP:  0.0281091 -0.147345

While the first data is matching with the first line of my input file, but the Current position seems to be 20 , which should be 1 in my case. then next position should be 2 , but as I shown the next one is 39.

Please help me what to do to work the ftell() correctly..

My input file is
Code:
0.137667 0.0595724
 0.102683 0.109343
 0.0508147 0.141131
 -0.00941674 0.149706
 -0.0681001 0.133655
 -0.115576 0.09561
 -0.144043 0.0418468
 -0.148821 -0.0187982
 -0.129114 -0.0763566
 -0.0881689 -0.121354
 -0.03272 -0.146388
 0.0281091 -0.147345

I also tried with
Code:
 long i=0;
 i= ftello(fh);

But no change..

Regards,
user_prady
I think ftell()function tells me the current curson postion , but I need the current line no. How to find the current line no , i guess NR do this jon in awk .But how to do it in c .

need help Badly..

Regards,
user_prady
# 3  
Old 03-13-2008
Data How to see the current line no in C language
Quote:
Originally Posted by user_prady
Hello friends,

I need help with ftell function in my programme, I can't figure out why I am not getting the file position what I supposed to get

Here is my code
Code:
void read_line(void *fh, double *input_re, double *input_im){
 
        double a, b;
        char s[50];
        int n;
        int i=0;
 
        if ( fgets(s, sizeof(s), fh) != NULL){
          
          i= ftello(fh);
       }
          printf("FILE Current Pos: %d\n ", i);
           printf("IMP: %s ", s);
          sscanf(s,"%lf %lf",&a,&b);
          
          *input_re = a;
          *input_im = b;
        }
        else{
                rewind(fh);
        }
}

I am calling the above function to read line from a file, assume that the file pointer is always in open mode to read from that file.

But My output is strange . The below is the begining of my output . but not the end..
Code:
 FILE Current Pos: 20
 IMP:  0.137667 0.0595724
 FILE Current Pos: 39
 IMP:  0.102683 0.109343
 FILE Current Pos: 59
 IMP:  0.0508147 0.141131
 FILE Current Pos: 81
 IMP:  -0.00941674 0.149706
 FILE Current Pos: 102
 IMP:  -0.0681001 0.133655
 FILE Current Pos: 121
 IMP:  -0.115576 0.09561
 FILE Current Pos: 142
 IMP:  -0.144043 0.0418468
 FILE Current Pos: 164
 IMP:  -0.148821 -0.0187982
 FILE Current Pos: 186
 IMP:  -0.129114 -0.0763566
 FILE Current Pos: 208
 IMP:  -0.0881689 -0.121354
 FILE Current Pos: 228
 IMP:  -0.03272 -0.146388
 FILE Current Pos: 249
 IMP:  0.0281091 -0.147345

While the first data is matching with the first line of my input file, but the Current position seems to be 20 , which should be 1 in my case. then next position should be 2 , but as I shown the next one is 39.

Please help me what to do to work the ftell() correctly..

My input file is
Code:
0.137667 0.0595724
 0.102683 0.109343
 0.0508147 0.141131
 -0.00941674 0.149706
 -0.0681001 0.133655
 -0.115576 0.09561
 -0.144043 0.0418468
 -0.148821 -0.0187982
 -0.129114 -0.0763566
 -0.0881689 -0.121354
 -0.03272 -0.146388
 0.0281091 -0.147345

I also tried with
Code:
 long i=0;
 i= ftello(fh);

But no change..

Regards,
user_prady
I think ftell()function tells me the current curson postion , but I need the current line no. How to find the current line no , i guess NR do this jon in awk .But how to do it in c .

need help Badly..

Regards,
user_prady
# 4  
Old 03-13-2008
fgets returns one line (assuming you ask it to read enough bytes to be sure):
Code:
/* change this */
i= ftello(fh);
/* to this */
i++;

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