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c file to extract real value from a txt file

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# 1  
Old 01-31-2008
c file to extract real value from a txt file
Hello Friends,,

I m really a new bee to C programms , please help me with a code..

I found some theads here similar to this but Not able to solve what exactly I want..


suppose I ve txt file as below.

abc.txt
Code:
12 23
10 11
131 159
12.2 13.8

Then I want to create a file which will read the file and store to
double pointer variable , as below


[code ]
double *a;
double *b
a = 12 // the pointer a should contain the real value 12
b = 23 //the pointer b should contain the real value 23
[/code]

Then I need to send these pointer value to another function.

Please help need urgently..
# 2  
Old 02-01-2008
Quote:
Originally Posted by user_prady
Hello Friends,,

I m really a new bee to C programms , please help me with a code..

I found some theads here similar to this but Not able to solve what exactly I want..


suppose I ve txt file as below.

abc.txt
Code:
12 23
10 11
131 159
12.2 13.8

Then I want to create a file which will read the file and store to
double pointer variable , as below


[code ]
double *a;
double *b
a = 12 // the pointer a should contain the real value 12
b = 23 //the pointer b should contain the real value 23
[/code]

Then I need to send these pointer value to another function.

Please help need urgently..
I am not sure if I understood you completely, but are you sure you need those double values to be stored in pointers to double values (not in doubles they point to)? Anyway, you can read your file line by line with fgets and scan each line with sscanf. Like this way:
Code:
#include <stdio.h>
#include <stdlib.h>

void process_doubles(double* a,double* b)
{
    *a+=0.1;
    *b+=0.1;
}
void parse_file(const char* szFn)
{
    FILE* fh;
    char szBuf[64];
    double a,b;
    fh=fopen(szFn,"r");
    while(!feof(fh))
    {
        fgets(szBuf,sizeof(szBuf),fh);
        if(sscanf(szBuf,"%lf %lf\n",&a,&b)==2) 
        {
            process_doubles(&a,&b);
            printf("%f %f\n",a,b);
        }
    }
}
int main(int argc,char** argv)
{
	if(argc<2) { fprintf(stderr, "Usage: %s <file name>\n",argv[0]);    exit(0); }
        parse_file(argv[1]);
	exit(0);
}

I omitted some really important checkings like if the file with particular file name actually exists, but in principal this should work.
# 3  
Old 02-01-2008
user_prady, is this a homework question? Please note that rule #6 prohibits homework questions from being posted.
# 4  
Old 02-04-2008
Quote:
Originally Posted by neutrino4
I am not sure if I understood you completely, but are you sure you need those double values to be stored in pointers to double values (not in doubles they point to)? Anyway, you can read your file line by line with fgets and scan each line with sscanf. Like this way:
Code:
#include <stdio.h>
#include <stdlib.h>

void process_doubles(double* a,double* b)
{
    *a+=0.1;
    *b+=0.1;
}
void parse_file(const char* szFn)
{
    FILE* fh;
    char szBuf[64];
    double a,b;
    fh=fopen(szFn,"r");
    while(!feof(fh))
    {
        fgets(szBuf,sizeof(szBuf),fh);
        if(sscanf(szBuf,"%lf %lf\n",&a,&b)==2) 
        {
            process_doubles(&a,&b);
            printf("%f %f\n",a,b);
        }
    }
}
int main(int argc,char** argv)
{
	if(argc<2) { fprintf(stderr, "Usage: %s <file name>\n",argv[0]);    exit(0); }
        parse_file(argv[1]);
	exit(0);
}

I omitted some really important checkings like if the file with particular file name actually exists, but in principal this should work.

Thank you Neutrino .. Really it helps me a lot..
GOD Bless You..
# 5  
Old 02-04-2008
Hi Neutrino !

I got you Smilie

File should be closed at the end of the function parse_file

Code:
fclose(fh);

Smilie
# 6  
Old 02-04-2008
Quote:
Originally Posted by matrixmadhan
Hi Neutrino !

I got you Smilie

File should be closed at the end of the function parse_file

Code:
fclose(fh);

Smilie
Dear Friends,

I am really in a great problem.
My problem is as follows

If I will send a counter to a function in c like read_line(counter);

Then it will read that line only which counter is pointing ,
Suppose I ve txt file like below

abc.txt
12.1
13.2
14.4

Then If I'll call the function as read_line(2);

It should read the 2nd line only and then put that value to a double pointer..

I mean one function call should read only the specified row,, and store it to a double pointer..

I need help badly..
# 7  
Old 02-04-2008
Quote:
Originally Posted by blowtorch
user_prady, is this a homework question? Please note that rule #6 prohibits homework questions from being posted.
No, its not a home work at all .
I am implementing C with my verilog code(HDL).

FYI This is going to be a chip of future for your mobile ..

Yet I am very confuse how to do this ..

With Regards,
user_pradyu
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