Thread: file input/output

i am trying to program a function that registers what card i have drawn. i want specific entries to be put on specific lines (ex. ace of spades on line one, 2 of clubs on line 52). i already have a blank file but i have no idea where to go from there. is there a function that lets me put my output on a specific line?

also for reference, here is my function for generating a blank file

Code:

void createfile()
{
    list=fopen("cardlist.txt","w");

    for(i=0;i<DECKSIZE;i++)
    {
        fprintf(list,"\n");
    }
    fclose(list);
}

Not in text mode, no. You have one of two options:
1) Use binary mode, and just seek to the spot you want and write that way. (You'll have to of course create the file so that it contains N bytes of data first, so that you can seek through them all.)

2) Use text mode, and read and write the entire file whenever you want to change its contents. (Read the file into an array, or whatever, write it all at once.)

Quzah.

is it possible for me to use /v and /r to move the cursor in fprintf or will that not work? im still a n00b so i dont know how to read a file into an array yet.

> i am trying to program a function that registers what card i have drawn
So why not use an array in memory rather than a file?

Or is this an exercise in using a file as an array?

Quicky tutorial

Code:

// your array, of MYTYPE, which is NUM elements long
MYTYPE array[NUM];

// open a file in binary mode
FILE *fp = fopen( "array_on_disk", "r+b");

// write the whole array
fwrite( array, sizeof(MYTYPE), NUM, fp );

// position at array[pos]
fseek( fp, pos * sizeof(MYTYPE), SEEK_SET );

// read array[pos] from the file
fread( &array[pos], sizeof(MYTYPE), 1, fp );