Questions tagged [fseek]

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PSet4 / Resize / Less: When to put the pointer back to the beginning?

I'm struggling with when to put the pointer back to the beginning. Every time I want to copy the same scanline vertically, I know I need to move the pointer on the input file from the end of the ...
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1answer
263 views

Understanding padding and fseek()

I have a simple doubt that, can padding be put for all of the scan-lines at once? What I mean to say is, that suppose, I have bi.biHeight == 10 then if I Write for (int k = 0; k < padding; ...
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1answer
39 views

Pset4 Resize. Code not working

I have been working on pset4 Resize for a few days now. I have tried researching online for the functions I didn't understand and been going through the lecture and walkthroughs and the notes but I'm ...
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1answer
144 views

Pset4 resize less comfortable, problems with fseek

I'm struggling a bit with resize. I think my headers work correctly as I do get a correct size output, but after the first horizontal line everything goes wack. My guess is that the fault lies in how ...
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1answer
78 views

CS50 Pset4 Resize - Vertical Sizing

I have no problems with the horizontal resizing but can't identify what is the problem in my code with the vertical resizing. Any help would be much appreciated. /** * Copies a BMP piece by piece, ...
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1answer
204 views

Pset 4 Resize fseek()?

I'm looking over my resize code rn, but have been stuck for a while now, was wondering if anyone could point me in the right direction. The resized images have colors beside green, which I would ...
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1answer
101 views

fseek doesent do what i expected

so what i am trying to do is to make fseek return to a new line as long as its smaller than factor i need to resize with. so fseek retruns to a start of line as long as its need to print those ...
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1answer
52 views

Vertical resizing with fseeks()

I am having a problem with fseek() to move the cursor back for copying line My code is below: int old_padding = (4 - (bi.biWidth * sizeof(RGBTRIPLE)) % 4) % 4; bi.biWidth *= n; bi.biHeight *...
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1answer
201 views

pset 4: resize adding in black pixels

Whenever I run my program on small.bmp passing in: $ ./resize 4 small.bmp larger.bmp I end up with this: It seems like the size is correct, but it's adding a black pixel after each line in the ...
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1answer
380 views

How to debug fseek not working as intended

I am pretty certain that my problem in this problem is my fseek in my vertical resizing for loop. Basically my idea is to print out horizontally resized code once per scan line always, then depending ...
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1answer
511 views

CS50 pset4 recover: buffer type and fseek questions

I have figured out a solution to recover, but my first attempt did not work. I'd like to understand a couple of things from my original attempt so I don't repeat the same errors in future code. ...
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1answer
101 views

Pset 4 Resize makes a very colorful picture (not green!)--padding problem?

Well, it looks like I'm not the only one having issues with padding (I suspect that's my problem). Specifically, if I test my version of resize with an enlargement factor of 2 (using small.bmp as ...
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1answer
284 views

PSET4 'resize' Padding is wrong

I'm stocked in resize My main problem is when it comes to enlarge a file that has some padding, i cannot enlarge it But when I run my program trying to enlarge a file with no initial padding, it runs ...
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1answer
257 views

pset6 load - why does fseek(file, 0, SEEK_END); size = ftell(file); not work?

after some struggles I just finished pset6. In particular my load function caused quite some pain. I thought I'd be spart and instead of reading the file in chunks of 512 bytes and doing a lot of ...
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1answer
179 views

How to use fseek along side arrays? Pset4 recover

I'm re-wrote this code and did not get any output or error. Tried valgrind and nothing was leaked. I suspect it's either: 1) my fseek is not moving my cursor in inpt 'card.raw' 2) and/or.. because ...
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1answer
118 views

pset4/resize. problem with resize code and i don't know what to do

I am trying to solve resize but I am facing problems and I don't know what to do. I don't even know is the problem with my info update or with fseek. I feel that there is something I miss or don't ...
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1answer
55 views

pset6 server2 load() fseek() return -1 [SOLVED]

I'm almost done with this one. However I have one more bug that I can't resolve. fseek is returning -1 only for some cases. errno's value is 29 after ftell, if that helps. check50 says: $ check50 ...
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1answer
912 views

what's the purpose of fseek in PSET4?

what is the purpose of even using Fseek() in pset 4 anyhow? I must be missing something Say we're looking at the original copy.c function. Basically, this is what I understand what's happening: ...
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1answer
240 views

Pset4 odd behavior

I can't really figure out while my code end up making a weird version for the resize pset. It compiles and run but the image is not quite what it's suppose to be. Thanks for your support! [EDIT: ...
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1answer
1k views

pset4 runtime error: unsigned integer overflow

my resize programm in pset4 has an error: resize.c:125:38: runtime error: unsigned integer overflow: 18446744073709551613 * 3 cannot be represented in type 'unsigned long' Here is my code: /** * ...
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1answer
382 views

pset4 resize fseek() - non proper work

I have similar question as there was asked, but can't find answer. Here is my code: /** * copy.c * * Computer Science 50 * Problem Set 4 * * Copies a BMP piece by piece, just because. */ #include &...
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1answer
147 views

pset4 resize problem with padding

I've been trying with this problem for more than a week now .. I guess I've figured out fseek() .. and the code works fine with files without padding, but it doesn't with ones that have padding ... so ...
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1answer
167 views

Pset4 resize - half working, padding issue?

So I am really having a hard time with pset4 resize. After 2 days I finally managed to have it resize the smiley correctly, but the small image is still incorrectly displayed (black bg, with glitchy ...
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1answer
308 views

pset4 Resize - Trouble Understanding Padding

I'm having a hard time understanding pset4's resize. Although I understand the theory, it's difficult for me to turn it into a program. I do understand that the scan line's total width must be a ...
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1answer
47 views

pset4 vert resize doesn't work with 1x1 px image

can someone point me in the right direction, when I resize small.bmp it works in all instances but check50 doesn't like it when it resizes smaller bmp's. I think maybe it has something to do with my ...
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1answer
2k views

Help with fseek and fgets

I am trying to fully grasp how these functions work. From the Reference50 website: fseek FILE* out = fopen("out.txt", "w+"); fputs("Team Bowden Fever!", out); char buffer[50]; fseek(out, 0, ...
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1answer
193 views

Please explain why copy.c skips over padding and how it then adds it back?

This is a two part question: 1) Why does copy.c have to skip over padding? 2) If it already skipped over the padding, why is it adding it back? Wouldn't this make extra padding? I have been reading a ...
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1answer
1k views

pset4 resize - fseek help (I think)

I'm on the verge of giving up. I've been stuck on this problem for weeks. I managed the headers, and I think I set up the loops right to write the pixels correctly. I just can't wrap my head around ...
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2answers
129 views

Yet again, problem with padding

I am having a problem with my code, and I think it has to do with the use of fseek. I have read a lot of the articles on the cs50 Stack Exchange, and tweaked my code a lot, but my problem still ...
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1answer
560 views

what is fseek() exactly doing?

I'm stuck since a while in the 'resize' task. Don't fully get my head around the padding. // read scanline pixel/pixel from infile // write pixels to outfile // skip padding // add padding back ...
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1answer
109 views

Pset4 resize.c outputting giant block of pixels

Firstly I apologize because there are many posts asking similar questions, but I've read over all that I could find, and it appears to me that my logic should be correct. This leads me to believe ...
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1answer
515 views

resize pset 4 confused on number of things

I think I have the headers correct except for the new bf.Size not to sure on that one. I am having real problems with resizing the bitmap and I can't figure out what it is, any hints or pointers in ...
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1answer
541 views

fseek in pset4(whodunit)

everyone, this is a segment of the code from pset4(whodunit) copy.c, and I'm wondering why the function fseek is needed. Given that padding cannot be read by fread, why not just simply use fputc to ...
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1answer
1k views

pset 5 resize vertically - use of fseek

I am struggling with the vertical resizing using the recopy approach. I read a pseudocode in an answer to another question in this forum and am trying to code it. I feel I am near but something is not ...