Questions tagged [whodunit]

whodunit.c, one of the assignments for Problem Set 4, will challenge you to manipulate the color value of pixels in a bitmap image in order to reveal a hidden image.

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How does fread progress through each byte in copy.c?

In copy.c (and the other apps using the same start code), how does freed know to read one byte after another? It seems to just do it automatically. Eg, this will read each byte, from first until bi....
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Pset4 Whodunit: Any way to enhance the image?

So I removed all the 'red noise' from the image but I don't recognize the person. My question is : Do I have to enhance the colors any more or do I need to just guess the identity of the person ...
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1answer
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Cannot use make: “Nothing to be done for whodunit.c”

For pset5 I did as suggested and copied copy.c to a new file named whodunit.c. I've left everything the same but hopefully changed the red pixel values. When I go to compile using make I get this ...
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Whodunit TO DOs

In "whodunit", I've successfully removed the red spots and the verdict.bmp reveals the face of a person in multiple shades of blue. My question is am I expected to further "enhance" the image by ...
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2answers
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Which colours do I manipulate in whodunit pset4?

Ok, so my code is working fine - I can manipulate the colours however I want. But which colours do I change?? I've used xxd to look at common pixels, I've tried bring some out in different ...
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1answer
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pset4 whodunit question with !==

Why doesn't !== work here? First if statement sets all the red colors to white. Second one, I was trying to make all other colors more darker so hidden image would become clearer. I was able to solve ...
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2answers
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Pset 4: Whodunit Red to white

When I run my whodunit on clue.bmp, I get the same red image as clue.bmp. Any advice on how to get rid of the red? Thanks in advance! Here is the code where I attempt to turn the red white: // ...
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1answer
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copy.c of pset4>>whodunit not creating perfect copies

When I run copy.c it creates a copy of clue.bmp but the clcp.bmp(the copy of clue.bmp) seems to differ according to diff. But when I try to do the same with smiley.bmp it works.
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1answer
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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
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how to answer whodunit questions

i don't know how to answer those questions there's no clue how to solve them i checked all the links doesn't include most of them, though i finished the pset. Any help would be very appreciated.
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Stuck on pset3, Whodunit

In Whodunit, you are asked to go into CS50 Lab and answer questions on how a file called copy.c works. They give you two links to BITMAPINFOHEADER and BITMAPFILEHEADER. Then, it says you should open a ...
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1answer
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Resize not resizing - only filling in center of image?

I tried following the pseudocode from the walk through and it compiled, however the image did not resize - rather the center filled in green. I hope my only problem is that I fail to skip over the ...
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1answer
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Did I finish the whodunit problem?

I have struggled to progress with the whodunit problem for hours: I watched the walkthrough from this year and older; I read various other forum question; and I read various documentation. The ...
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1answer
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How to save images of whodunit into the CS50 IDE

I had downloaded the Images and the codes but I can not understand that How to save the downloaded file into the CS50 IDE. If someone knows that Please Help me!!
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1answer
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How do I resolve a `for loop initial declarations` error while compiling?

I just copied copy.c to whodunit.c. Then I saved and tried to compile the program by running make whodunit. This resulted in the following error. whodunit.c: 73:5 error: for loop initial ...
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1answer
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why image color is not changing in whodunit?

I have made the below mentioned changes in my whodunit file but still the new image that is created is exactly similar to clue.bmp someone please help...
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pset4 whodunit.c could not open the infile please help

My program does not open the infile I am trying to find it out but I could not please help. Thank you! // Copies a BMP file #include <stdio.h> #include <stdlib.h> #include "bmp.h" int ...
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0answers
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pset4 how to enhance the colors in the background

How do I enhance the colors in the background. I've added white colors to the image, making it much more visible, but not sure whodunit. I am trying to enhance the sky blue in the image so that I can ...
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3answers
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Need help, on pset4, whodunit. I am trying to change all instances of red to white

Need help, on pset4, whodunit. I am trying to change all instances of red to white, instead of black. When I changed all instances of red to black, I was able to see a bit of the image beneath it , ...
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1answer
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Pset5 - Whodunit

What do we have to do in Pset 5 : Whodunit? I know we need to analyze a file, but all I see is a lot of red pixels.
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1answer
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whodunit section

I've just started doing pset4. I'm stuck in whodunit section itself, I've no idea about the questions in whodunit section. After opening the file, there are list of todo's corresponding to each number ...
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1answer
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Person in pset4 whodunit

Hey guys I am doing pset4 "whodunit" of fall 2014 from cs50.harvard.edu. I successfully eliminated the red noise and enhanced other colors.I am seeing the image of someone holding something hidden ...
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1answer
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pset4 WHODUNIT Is there a way to wget the files on the CS50 IDE?

I'd like to complete the whodunit using CS50 IDE. Is there a way to use wget to get the files from WHODUNIT so i can work on them?
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what's the picture I should see

I wrote the code for whodunit.c but when I looked at most of the questions in here, all of it shows a picture of a man, for me this is what I get: [removed per academic honesty policy] did they ...
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1answer
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pset4 whodunit should it be clear as day?

After playing around with the colors and not being able to get it perfect. Is the bmp that we create using whodunit ment to be clear as day? mine is faint, i am just not quite there yet or is that how ...
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1answer
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Pset4 whodunit yellow background

I don't know what part of my code is wrong. I tried changing the value of triple.rgbtBlue, triple.rgbtGreen and triple.rgbtRed but the result is the same, with an yellow background. Please help. for (...
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3answers
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Red has been turned to white, now how do I turn blue to black?

Red has been turned to white, now how do I turn blue to black? I have written a new loop next to the first loop but it does not work. if image is all blue red = 0x00 blue = 0x00 green = ...
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1answer
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Verdict.bmp: image not clear && no such person seen anywhere in course material

I will be grateful for help on the part of recognizing the person. 1) Am I right assuming that if I have removed red pixels and thus revealed underlying picture, then I am done with the code, even ...
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1answer
865 views

What is the value of green and blue?

"If the R, G, and B values of some pixel in a BMP are, say, 0xff, 0x00, and 0x00 in hexadecimal, that pixel is purely red, as 0xff (otherwise known as 255 in decimal) implies "a lot of red," while ...
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why does the picture become “more” red in whodunit?

Inside the for loop // temporary storage RGBTRIPLE triple; // read RGB triple from infile fread(&triple, sizeof(RGBTRIPLE), 1, clue_ptr); if(triple....
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1answer
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Why is file pointer null on Whodunit and how can I fix?

(gdb) b main Breakpoint 1 at 0x804869e: file whodunit.c, line 18. (gdb) r infile outfile Starting program: /home/jharvard/Dropbox/pset5/bmp/whodunit infile outfile Breakpoint 1, main (argc=3, argv=...
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PSet3 WhoDunit open ended question materials

I'm currently on Pset3 WhoDunit. Part of the task is to answer open-ended questions. What I don't quite get is the connection of these questions to the Lecture or Shorts - some of the questions are ...
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pset4 how does incrementing j help to iterate over pixels?

I'm currently working my way through understanding the code of copy.c used in "whodunit" and "resize". This loop is supposed to iterate over the scanlines of a Bitmap (by incrementing i) and within ...
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1answer
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pset4 whodunit can't understand the infile pointer

In this whodunit copy.c the input filenames and output filenames are entered as command line arguments but I couldn't understand that How does inputting the file name will point to the file. // ...
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1answer
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Starting whodunit

I just finished pset3, so now I'm starting on pset4, and I'm not quite sure how to start whodunit? I think you should copy the clue (I'm not sure where to copy it to though) and iterate over each of ...
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1answer
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whodunit message is very blue pale. is it part of the homework to learn to put the blue pale darker ?

I understood that making all the red going away, make the color cyan. When I put all the colors black, the message was still in red. The message in blue cyan is not very clear but I can read it. It ...
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1answer
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ps4 Whodunit - how to code white colors

I have 2 questions. 1 - I did succeed to see the message with replacing red by white. But I can't replace the red by white ? what I am doing wrong please ? // read RGB triple from infile fread(&...
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1answer
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Pset4 how does the copy loop work

Ive just got to pset4 and it seems a bit of a jump from pset3, I'm trying to understand how everything works before diving into the problem. This loop in my mind which is copying the bmp files goes ...
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1answer
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Pset4 Whodunit — Why does darkening the pale blue add the red back in?

I successfully removed the red from clue.bmp and got the light-blue mug shot on a white background. Then I added another section of code to darken the blue (by reducing the blue and green values by ...
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1answer
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Pset4 whodunit I have much enhanced the pic it can be seen easily now, But still cant recognize the person

Here is the image, I am not american maybe he is american celebrity. [![enter image description here][1]][1] spoiler image removed
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1answer
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pset4 - Whodunit. Pale colors

Anyone on Whodunit, interested in discussing it a bit? I managed to remove red noise and ended up with a picture of faint shades of greenish blue (or maybe the other way around - blueish green ;-) ) ...
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1answer
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Pset4 whodunit question

I'm trying to change the blue in clue.c. Right now, I made all the red into white, but i'm confused why my code doesn't change the remaining into black? Here's what i have. I'm trying to say, if it's ...
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1answer
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Trouble opening pset4 Clue.bmp

I'm having trouble opening the clue.bmp file. Every time i try to open the file to work on whodunit.c it seems to freeze gedit and i have to close the window and reopen gedit. DOes any one know What ...
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1answer
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Use of check50 in pset4

I would like to test my whodunit.c that I wrote for pset4 as described here with check50. In the last psets there was always a code line for the proper call of check50 in the pset-description, like ...
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Whodunit: Copy.c help

for pset 4 whodunit, when i do "cp copy.c whodunit.c" it says "cannot stat 'copy.c': No such file or directory" My directory is cd "/ home / jharvard /Dropbox /pset4"
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Why is diff showing two identical bmps different?

In the whodunit assignment, when I used the copy.c given in the pset4.zip on smiley.bmp and executed the diff check, there was no message shown. However, when I used the copy.c and diff on the clue....
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I could not get the desired output because when I click the verdict I could not find who done it

// Copies a BMP file include include include "bmp.h" int main(int argc, char *argv[]) { // ensure proper usage if (argc != 3) { printf("Usage: copy infile outfile\n"); ...
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Why I am getting blank verdict on whodunit?

// Copies a BMP file ​ include include ​ include "bmp.h" ​ int main(int argc, char *argv[]) { // ensure proper usage if (argc != 3) { printf("Usage: copy infile outfile\n"); ...
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1answer
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PSet 3: Help with colors for “whodunit”

I've successfully decoded the solution to "Whodunit" from CS50 2018 (won't put the spoiler here, though will say the culprit's name has six letters), but will admit it was a lucky guess involving ...
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What are primitives?

In the WHODUNIT problem set in week 3 it says: "Open up bmp.h, and you’ll see actual definitions of those headers we’ve mentioned, adapted from Microsoft’s own implementations thereof. In addition, ...