LinuxQuestions.org - binary file problem

- Programming (https://www.linuxquestions.org/questions/programming-9/)

- - binary file problem (https://www.linuxquestions.org/questions/programming-9/binary-file-problem-287860/)

binary file problem

okay this is a piece of code....

int fdf;
int rcf;
fdf=open("output7",O_WRONLY|O_CREAT|O_TRUNC,0666);
rcf=write(fdf,genespect,len);
close(fdf);

genespect is pointer to a double array
it was declared as

double *genespect;

genespect=(double*)malloc(len*sizeof(double));

after the execution i see that the file output7 has been made.it probably has
legit data too...i cant open it....gedit does not open it .....

i basically want this to be an ascii file with one number per line...
how do i do that?
i know it isnt like that cos' gnuplot isnt able to plot it(it requires the file to be in one number per line format)

thanks,
dhananjay

You're best off using stdio functions:

Code:

fp = fopen("output7", "w");

for(i = 0;i < len;++i)

  fprintf(fp, "%f\n", genespect[i]);

fclose(fp);

"binary files" and "one number per line" don't mix. Binary files have no concept of newlines so they also don't have any concept of lines.

itsme86 already told, but I'd already made up an example. I'll post it anyway.

Code:

#include <stdio.h>

#include <stdlib.h>



int main()

{

    int i, len;

    double *genespect;

    FILE *file;



    len = 2;

    genespect = calloc(len, sizeof(double));

    if (genespect == NULL) {

        fprintf(stderr, "Error: Ouot of memory\n");

        return 1;

    }

    

    /* Just two values here */

    genespect[0] = 22.0/7.0;

    genespect[1] = 355.0/113.0;



    /* Open file */

    /* Using higher level stdio here */

    file = fopen("output.txt", "w"); 

    if (file ==NULL) {

        perror("Opening output file.");

        return 1;

    }



    for (i = 0; i < len ; ++i) {

        /* Using stdio calls you can do convenient

        * printf-conversion while writing to a file.

        */

        fprintf(file, "Value #%d: %f\n", i, genespect[i]);

    }

    fclose(file);

    return 0;

}

Seriously man,you guys are lifesavers!!!!!!
it worked!!
dhananjay