Questions tagged [c]

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C Preprocessor Output: What is <built-in>

I wrote one of the most simple programs I could imagine: int main (void) { int a; } As you can see, there are no include files. The purpose is to understand a little bit more about the ...
2
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5answers
2k views

How can I get the cs50.h to run in Visual Studio Code?

I downloaded both the cs50.c and cs50.h files from GitHub and put them in the folder where all the header files are. VSC even recognizes the #include <cs50.h> in the code but I get the error in ...
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2answers
1k views

passing argument 1 of ‘strlen’ from incompatible pointer type

How to make this working? How to properly find the length of these 8 listings? Whenever I execute it gives me following error. *passing argument 1 of ‘strlen’ from incompatible pointer type * #...
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0answers
62 views

CS50, pset2, crack, suggested dictionary file

I am taking cs50 on edx and I am currently on pset2, crack. I want to find a dictionary file that has a fair (maybe over 50,000?) amount of words in it to encrypt and compare them with the hashed ...
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0answers
2k views

Valgrind says "Invalid read of size 4" while freeing memory recursively in a trie

My PSET "mispelling" works fine and contains no memory leak but when I run the program with Valgrind it says Invalid read of size 4. My unload function calls a deleteTrie function which looks like ...
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0answers
22 views

Why do Escape Sequences in C work differently when I compile code by using GCC?

Why do Escape Sequences in C work differently when I compile code by using GCC? For example, Input: #include <stdio.h> int main(void){ printf("Hello world\n"); } Output in CS50 ...
0
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1answer
20 views

How does the CS50 IDE recognize C functions in advance?

I notice that functions like printf() and toupper() appear in blue without the relevant #include statements in files with names ending in .c. What is happening under the hood to make this happen?
0
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1answer
8 views

error : function definition not allowed here pls help

i got this error message pls help $ make triangle clang -ggdb3 -O0 -std=c11 -Wall -Werror -Wextra -Wno-sign-compare -Wno-unused-parameter -Wno-unused-variable -Wshadow triangle.c -lcrypt -lcs50 -...
0
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1answer
13 views

pset2//caesar : strspn result

I'm struggling to understand : (argc != 2 || argv[1][strspn(argv[1], "1234567890")]) It works, but I'm trying to understand what's going on inside the if evaluation, and the value argv[1][...
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0answers
18 views

CS50 Speller: valgrind test says that bytes are still reachable in 3 blocks

I'm currently at the CS50's pset5, and am working on the "Speller" problem. I managed to do all functions and don't have any compile or runtime errors. When using check50, though, I receive ...
0
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0answers
11 views

Cannot Compile CS50 Library

I've been running into this problem lately. Here's one of my code: #include <cs50.h> #include <stdio.h> #include <string.h> // ... for (int i = 0; i < voter_count; i++) { ...
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0answers
8 views

Library = Collection of functions?

do I understand it right, that in that library there are only a collection of functions inside that i can use?
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1answer
30 views

CS50 - PSET 4 - Filter - Edges

//Pixel buffer RGBTRIPLE pixelBuffer[height][width]; //Iterates on every pixel and calculates Gx and Gy for (int i = 0; i < height; i++) { for (int j = 0; j < width; j++)...
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0answers
6 views

Error with calculating Egdes in Pset4 Filter (More) Detect Edge problem

// Detect edges RGBTRIPLE new_pixel(int i, int j, int height, int width, RGBTRIPLE image[height][width]) { int redx; int bluex; int greenx; int redy; int bluey; int greeny; ...
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3answers
19 views

Error retrieving return values ​from a function

I am currently studying coding in C language and I have doubts about the return of functions, what I am trying to do is the following: Call the number () function and pass 3 values ​​of the integer ...
0
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1answer
24 views

Help to finish my problem - Check50 - Pset4 - Filter Less

I am coding the sepia filter, it is already working, but it does not pass the check50. I think of according to the check50 report, that there is some problem of precision in the calculations, but I ...
0
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1answer
21 views

question on Week 1 lecture

I just have a small question. David showed how to compile the source code "Hello.c" file using the make command to make the executable machine code file "Hello" in the lecture. I ...
0
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1answer
18 views

PSet3 Tideman , error with updating ranks array

bool vote(int rank, string name, int ranks[]) { for (int i = 0; i < candidate_count; i++) { if (strcmp(name, candidates[i]) == 0) { ranks[rank] = name; ...
0
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1answer
68 views

My do-while loop does not work

do { number = get_long_long("What is your credit card number? "); } while((number < 1000000000000) || (number >= 10000000000000000)); This loop is not accepting inputs. I do not ...
0
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1answer
40 views

pset4 Blur calculation does not work properly

for some reason I can't get my calculation for the blur value running. The pictures are really odd and contain crazy colors. Any ideas to why this could be the case? I compared it already to working ...
0
votes
1answer
7 views

Caesar - ASCII to char conversion problem

Going through the CS50 exercise Caesar, and I'm still very new to C. My code to validate the key is all working, but as I try to convert from plaintext to the cipher text I keep getting caught up with ...
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0answers
10 views

Pset4_ Blur: (more comfortable)Problem, I think there is a small bug, but I can't find it

I was working on my code(sorry for it being so long), then I kept getting the same error and I don't understand why :) blur correctly filters middle pixel :) blur correctly filters pixel on edge :) ...
0
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1answer
38 views

Pset3 Tideman: Why is my sort_pairs function not working?

I'm green on all the criteria before sort_pair. Here's my code so far: // Sort pairs in decreasing order by strength of victory void sort_pairs(void) { // TODO // Create array of strengths of ...
0
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1answer
15 views

Seg fault (storing file pointer as NULL initially maybe?)

// img file pointer FILE* img = NULL; char* file_name = NULL; int file_count = 0; int bytes_written = 512; // repeat until end of memory card while (bytes_written == 512) // ...
0
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1answer
62 views

pset1 credit: I am unable to identify what's wrong in the logic of my code?

Kindly tell me what mistake have I made in this program? pset1 Credit: (my code) https://pastebin.pl/view/5646dbf1
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1answer
82 views

pset3 tideman cs502020 locked pairs error

I am new to coding and I am trying to solve the locked pairs part of the Tideman problem. Currently, I am receiving the following two errors: :) lock_pairs locks all pairs when no cycles :( lock_pairs ...
0
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1answer
244 views

cs50 array initializer must be an initializer list

i have started coding in c but i keep getting errors i don,t know how to solve maybe it is because i am used to coding in php language but i hope anybody can help me #include <stdio.h> #include &...
0
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1answer
79 views

Error: function definition is not allow here What error is this?

main.c:10:24: error: function definition is not allowed here int read( int a[9][9]){ ^ main.c:36:24: error: function definition is not allowed here void show(int a[9][9]){ ^ main.c:58:24: error: ...
0
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1answer
42 views

cs50 speller code complies and run also successfully. but it not qualifying for big board

:) dictionary.c and dictionary.h exist :) speller compiles :( qualifies for Big Board expected exit code 0, not 139 :| passes benchmarking can't check until a frown turns upside down how to fix this *...
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0answers
51 views

cs50 pset3 tideman lock pairs and print winner function are not working rest all are working

in lock pair (lock_pairs skips final pair if it creates cycle is working) rest all lock_pair and print winner is not working. #include <cs50.h> #include <stdio.h> #include <string.h> ...
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0answers
4 views

Json header file for C

Is any header for json in C, form which we can parsh any json file of 2D, 3D , etc. or is any other way to work with json in C programming language. from which we can parsh our json data and get it ...
0
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1answer
42 views

pset4 - can't figure out what i'm doing wrong - recover

This is the code: #include <stdio.h> #include <stdlib.h> int main(int argc, char *argv[]) { if (argc != 2) { return 1; } FILE *file = fopen(argv[1], "r&...
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1answer
81 views

Having trouble with Cash but does not know what is wrong

I am having trouble with my code for pset1/cash. When I check the code, this is my output: :) cash.c exists :) cash.c compiles :( input of 0.41 yields output of 4' expected "4\n", not "...
0
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1answer
23 views

Struggling to understand file I/O

everyone. I'm just starting my journey in learning to code, starting with C. And for the past few months, I've been struggling to understand file I/O. More often than not, I don't get the output I'm ...
0
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1answer
33 views

i m getting segmentation fault in my code for cs50 caesar

#include <stdio.h> #include <cs50.h> #include <stdlib.h> #include <ctype.h> #include <string.h> int main(int argc, string argv[]) { //getting correct input for KEY ...
0
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1answer
11 views

when I compile my program this bug appear. error: control may reach end of non-void function [-Werror,-Wreturn-type] }

bool check_valid_key (string s) { for (int i = 0, len = strlen(s); i < len; i++) { if (!isdigit(s[1])) return false; return true; } }
0
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1answer
63 views

Find hex values inside a string in C?

I have a long string "given_string", and I'm trying to find hex values within that string. Here's a simplified example: /* Find a sub-string in a given string: */ char * given_string = &...
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0answers
28 views

Recover Assignment Memory Leak and Insufficient Recovery

I am trying to complete the assignment given by CS50x (Harvard Community Online, edX.org), and while it successfully recovers images, valgrind is telling me that there are memory leaks that happen in ...
0
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1answer
190 views

incompatible pointer types passing 'string' (aka 'char *') to parameter of type 'string *' (aka 'char **')

Im writing a funtion that takes string as a argument and gives back a integer. This function counts lenght of a string entered at the command line argument. I get an error :" incompatible pointer ...
0
votes
1answer
82 views

Pset1 Creating and Changing Directory Does Nothing

For the first problem set, I attempted to create and change the directory with the following commands: $ mkdir ~/pset1 $ cd ~/pset1 $ mkdir ~/pset1/hello $ cd ~/pset1/hello Despite doing these ...
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0answers
367 views

CS50 - PSET2 - Substitution Segmentation fault

I keep getting 'Segmentation fault' every time I run the code(mentioned below). The code is compiling just fine. It's asking for input and is returning required message when the command line argument ...
0
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0answers
23 views

Why do I have a segmentation fault in my Caesar coding from pset2?

#include <stdio.h> #include <math.h> #include <cs50.h> #include <ctype.h> #include <string.h> #include <stdlib.h> int main(int argc, string argv[]) { if (argc != 2)...
0
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1answer
68 views

PSET5 speller memory leak and dictionary not unloaded

I have been looking at this for about 5 days now and I can´t find where I am leaking memory or if I have any problems with my code logic. Everything compiles and Valgrind output is below. I am ...
0
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2answers
284 views

error: result of comparison of constant with boolean expression is always true

So, I want to make a do-while loop, repeating the question for an input, so check if the input is in a range between 340000000000000 or 379999999999999 and my code is generating a compilation error: ...
0
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1answer
20 views

Split double digits into 2 seperate integers

i'm currently trying to do credit.c in pset 1, and I've managed to get every other digit separated and multiplied by 2, then added together, the problem is the next step "Now let’s add those products’ ...
0
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1answer
75 views

Recover function in pset4

#include <stdio.h> #include <stdlib.h> #include <stdint.h> #include <stdbool.h> /* Open memory card Repeat until end of card: Read 512 bytes of data into buffer If ...
0
votes
1answer
54 views

CS50 PSet 4 Recover, Segmentation Fault

My code compiles, but whenever I run Check50, I get a segmentation fault error for each category. Would definitely appreciate any help identifying where the problem can be fixed! #include <stdio.h&...
0
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1answer
100 views

PSET4 Recover - Can't Read Card

Having a problem with Recover. The debugger shows that "buffer" is always 0000. Tried everything I could think of here. Any ideas? #include <stdio.h> #include <stdlib.h> #include <...
0
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2answers
288 views

CS50 pset3 plurality program gives error for print_winner function (did not print both winners of election)

I have finished the plurality program for pset3 of cs50, but upon running check50 on my code, I receive the following error directed towards the print_winner function: :) plurality.c exists :) ...
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0answers
53 views

I am having trouble with the 2020 pset4 Recover assignment and even though my code compiles, it doesnt work, its not recovering the images

EDIT: I posted this 17 days ago please help. Heres my code and it wud be great if someone cud help A.S.A.P. thankyou! #include <stdio.h> #include <stdlib.h> #include<stdint.h> #...