Thread: reading/writing to file

Ok so what I want to do it store an array of ints, in this case:

Code:

int a1[16] = {5,10,15,20,25,30,35,40,45,50,55,60,65,70,75}

and later read them from file.


So right now I produces the file "data.dat" which is just a .dat file containing "051015202530354045505560657075"

Now I want to read from disk, but am having a problem. How do I read two spaces and store it into an int?

Here is my code with write_File commented out (so that it just reads):

Code:

#include <stdio.h>
#include <stdlib.h>


void write_File(int* a1);
void read_File (void);

int main()
{
int i;
int a1[16] = {5,10,15,20,25,30,35,40,45,50,55,60,65,70,75};

//write_File(a1);

read_File();
return(0);
}

void write_File(int* a1)
{
    int i;

    for(i=0; i<=14; i++)
    {
        FILE* fts;

        fts = fopen("data.dat", "a");

        if (fts)
        {
            fprintf(fts, "%d" , a1[i]);
            fclose(fts);
        }


        else
        {
            printf("Error writing to file!\n");
        }

    }

}

void read_File (void)
{

    int i;
    int a2[16];

    for(i=0; i<=14; i++)
    {

        FILE* fts;

        fts = fopen("data.dat", "r");

        if (fts)
        {
            fread(a2, sizeof(int), 15, fts);
        }


        else
        {
            printf("Error reading to file!\n");
        }


        for(i=0;i<15;i++)
        {
            printf("%d\n", a2[i]);
        }

            fclose(fts);

    }

}

A simpler solution is to change write_File to write with fprintf(fts, "%d " , a1[i]); then you read with fscanf.

EDIT:
Also, I notice that you are repeatedly opening and closing the file within the loop. Don't do that. Open once, loop to read/write, then close.

Ah this is so awesome! Thank you so much!! Really cut down the code for me and makes sense