Questions tagged [fopen]

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Pset5, speller 'could not open text'

So I wrote my load function and everything looks good, so I had it return true so I could move on and test other parts of the program. My problem is that speller.c won't load my text. I made a custom ...
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1 answer
507 views

PSET4: fgets returns odd characters instead of what's in .raw

I know the first few lines of 'card.raw' are (by opening in a texteditor): bit.ly/18gECvy ˇÿˇ‡JFIFHHˇ€Cˇ€Cˇ¿Vˇƒ Currently all I want the app to do is print back what's in the .raw file, and then ...
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2 answers
90 views

In recover.c, how do you name each image file a seperate name?

Is this even necessary? Will the computer automatically name each file? Or will it use the name designated in fopen()?
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1 answer
557 views

How to open multiple files with fopen()

I was wondering if it's possible to dynamically pass through a string into fopen(). E.g. String s = Depends-on-user-input.txt And then is there a way to do Fopen(s, "r"); I've tried to use ...
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1 answer
66 views

pset3 recover is fopen changing the first value in my buffer?

My code for pset3 works and recovers all the images as it is supposed to however I realised that when I call fopen the first value in my buffer array becomes 0 I fixed this by changing the value back ...
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1 answer
206 views

PSET4 Recover images not showing correctly

Here is updated code with answer. #include <stdio.h> #include <stdlib.h> #include <stdint.h> int main(int argc, char *argv[]){ if (argc != 2){ ...
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0 answers
745 views

How does fopen() work with arrays?

For the following code: #include <stdio.h> int main(int argc, char *argv[1]) { char *x = argv[1]; char a[5]; char b[5]; FILE *fn = fopen(x, "r"); FILE *fp; for(int i = ...
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1 answer
69 views

Files Won't Open In The Directory

Hey so I have written some code, needless to say I am a bit confused, I have pasted it below. It is for pset4 recover and so I want to open the files that are contained in card.raw, however despite ...
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2 answers
523 views

PSET4: Recover - How to check if already found JPEG?

Need to figure out how to identify if I already have a JPG that I have found. So that if I have it will close the previous image and then start a new one. My thought was that I need to check if my ...
1 vote
2 answers
33 views

What is the value read in the following code? if the open.txt file contains 1 to 10 numbers

#include <stdio.h> #include <stdint.h> #include <stdlib.h> typedef uint8_t BYTE; int main(void){ FILE* open = fopen("open.txt","r"); BYTE read; fread(&read,...
1 vote
1 answer
377 views

Recover.c Segmentation Fault

Pseudocode: declare counter declare filename[8] main Open input Declare buffer do read(512 bytes into buffer from input) while (not start of jpeg) do write filename open ...
0 votes
1 answer
108 views

PSET8: fopen() not working for import

For pset8, fopen() keeps returning FALSE. The relevant part of my code is below: #!/usr/bin/env php <?php $file = ($argv[1]); if(file_exists($file) == 0) { exit("File does not exist.\n"); } ...
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1 answer
884 views

Why I cant open the input file using fopen

I have just finished reading the chapters mentioned in the specs of pset4, before starting the pset i thought about practicing so wrote a program given in the book to copy a file to another.I have ...
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1 answer
223 views

pset4 recover.c valgrind claims there is unfreed memory. I'd like to know how/why?

I just finished recover.c in pset4. It compiles, runs, and creates all the jpgs just fine, but valgrind gives me the following leak summary (full leak summary at bottom): ==15709== LEAK SUMMARY: ==...
0 votes
1 answer
115 views

pset4 recover not naming the first file correctly?

This is an odd one. I've managed the get the code to work and output all 50 jpgs as expected with the exception of the first one. It's creating the file but not naming it correctly (not even adding ....
1 vote
1 answer
2k views

Correct use of fopen, fclose, file pointers

I found this problem while working on recover.c. My program recovers all the image files, check50 says everything's cool, but when I run Valgrind, it gives me a ton of errors. After some tests, I ...
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1 answer
699 views

Why can't my recover program open card.raw?

card.raw is in the same folder as my recover program. When I try to execute it, my program spits back to me "file could not be opened" which is what I programmed it to do if the file pointer returns ...