Questions tagged [c]
The c tag has no usage guidance.
556
questions
0
votes
1answer
10 views
Helping with Valgrind "Conditional jump or move depends on uninitialised value(s)" in simple C code
So right now my code seems to me like it doesnt have issues, it looks like this:
int i;
char hello[] = "Hello World!";
char * str = malloc(strlen(hello)+1);
for(i = 0; i < ...
0
votes
0answers
6 views
pset4 blur, tried this method, I can't figure out what is the problem with my code
It compiles, and passes the check for pixels in the corner, but fails every other test,
before I added the logic for the corners and edges it passed the test for the middle pixels also. I can't ...
0
votes
1answer
16 views
Use of undeclared identifier 'num'
I dont really know where im wrong. it gives me "use of undeclared identifier 'num'" i allready tried to solve it but i have no clue of what is going on
#include <stdio.h>
int maxc = 0,...
0
votes
2answers
16 views
for- loop stop if output A
on pset2/caesar
and only when ciphertext[i] = A or a
for loop stopped ????
0
votes
0answers
8 views
Pset3: Tideman - Sort_pairs
Check50 says that my sort_pairs function is wrong, but with the tests I've used, everything is alright.
Here's the code:
void sort_pairs(void)
{
int biggest_strength_of_victory = preferences[pairs[0]....
0
votes
1answer
23 views
How to convert an unsigned char to a string?
I'm needing to collect byte by byte of an unsigned char and convert it to a string, how can I do that?
I've tried everything but it didn't work.
My example code:
#include <stdio.h>
#include <...
1
vote
1answer
17 views
Mario problem: Program got stuck at user input
// ** Below is the code of mario pset1, its taking input of width multiple times and not executing step after input//
#include <cs50.h>
#include <stdio.h>
#include <math.h>
int main(...
0
votes
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
votes
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?
1
vote
1answer
28 views
'stadio.h' file not found
#include <stadio.h>
int main(void) {
printf("hello, world");
}
when i type make hello
clang -ggdb3 -O0 -std=c11 -Wall -Werror -Wextra -Wno-sign-compare -Wno-unused-parameter -Wno-...
1
vote
1answer
22 views
Unable to confirm user input is a number using isdigit in c
My code is attempting to;
take user input from the command line;
check if the input is a whole number;
confirm positively if so;
confirm negatively if not;
however all numbers return a negative ...
0
votes
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
votes
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][...
0
votes
1answer
17 views
function output?
I can't get this function to output the desired value of 0.07.
#include <stdio.h>
#include <cs50.h>
#include <math.h>
float i = 1.32;
float quar_val = 0.25;
int func(float val, ...
0
votes
0answers
19 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
votes
1answer
35 views
pset4 filter blur less got stuck
i have been working on blur and it works just fine as i run it. but when i run check50
i get this :
:( blur correctly filters middle pixel
expected "127 140 149\n", not "145 160 169\n&...
0
votes
1answer
36 views
credit pset1 cs50 sum while loop
I was doing the credit problem with the visa test card in the page: 4003600000000014
It passed that test, however in other tests it doesn't pass.
I think it's a matter of the sum that it can't compute ...
0
votes
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++)
{
...
0
votes
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?
0
votes
1answer
17 views
Why is an Array longer then the input?
why we can access more information than the lenght of the array?
I thought that after the Null (0) the array ends. Why we can access position 40?
0
votes
1answer
31 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++)...
0
votes
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;
...
0
votes
1answer
32 views
PSET4 RECOVERY does not recover images correctly
I have started working on PSET 4 RECOVERY. My program compiles successfully, it goes through the first 3 tests no problem, but for the love of me I cannot seem to find the problem.
It just does not ...
0
votes
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
votes
1answer
20 views
Recover PSET4 Corrupt images
i was working on pset4 recover and my code finds all the image, but everytime it writes to the image the image got corrupted, and i cant find the issue, checked the debugger and it seems going the way ...
0
votes
1answer
25 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
votes
1answer
49 views
pset4 - (Filter Less ) - Doubts with malloc()
I'm performing the problem set from pset4 to the (filter less) part. I wish to use malloc() to my advantage to speed up image filtering and maybe check50 will accept my solution to the problem.
I ...
1
vote
1answer
46 views
Recover - segmentation fault and other general problems
Hey guys so I've hit a bit of a wall with Recover, when I run my program I get segmentation fault but I also don't know how to end off one jpeg when another header pops up? In essence, I'm not sure ...
1
vote
1answer
48 views
Lecture 5 Linked Lists: What's going on under the hood?
Sheepishly I must admit I am having difficulty understanding how Linked Lists are implemented. Spent an hour and a half just on this part. The following partial code is from the lecture (comments ...
0
votes
1answer
68 views
PSET3 Tideman - What to do with the lock_pairs function?
Can someone please help me with the lock_pairs section of the problem? The lock_pairs function is killing me. I get that you have to compare the pairs to each other and then return false or true in ...
0
votes
1answer
31 views
PSET 1 Credit Card Checksum doesn't add up
I'm having my issues finding the right answer as this is non code related.
The checksum says: "If the total’s last digit is 0, the number is valid!"
This is a credit card number that is ...
0
votes
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
votes
1answer
63 views
Credit (Pset1) - Checksum problem
so I have a problem with the Credit exercise from pset1. I updated my code today after realizing that I didn't split up the digits of the product of the current digit in the card number and 2 and ...
0
votes
1answer
11 views
Command debug not found
when I try to run the command debug
debug ./scores
the message that returns is that :
Command 'debug' not found
0
votes
2answers
34 views
stuck on readability pset2
Hi I am stuck on readability and am not sure what i am doing wrong
$ ./readability
Text: one fish. two fish. red fish. blue fish
8
3
42
13
Grade 13
and my code:
#include <stdio.h>
#include <...
0
votes
1answer
471 views
Lab 8 // Resetting button colors not working properly
I am doing the lab 8 trivia question and I am try to reset all the colors of the buttons when you press another from the rest. I am not sure how to do it. I have the function for resetting the colors ...
0
votes
1answer
19 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
votes
1answer
20 views
I have included all the libraries, yet it shows errors (pset2)
This is my code:
#include <stdio.h>
#include <cs50.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
int main (int argc, string ...
0
votes
2answers
49 views
Speller.c, get correct result on my machine, wrong on check50
Good day,
I am struggling with speller.c. When I run the program on my machine I get the correct result compared to the keys but then when I use check50 to check I get all wrong.
I have narrowed the ...
0
votes
2answers
60 views
Check50 accepts all but last 2 tests. pset1/credit
I've been trying to fix this on my own for a bit but I wasn't able to find an answer online. My credit program passes all check50 test's except for the last two (identifies 4111111111111113 as INVALID ...
0
votes
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
votes
2answers
36 views
What modification do I need to shorten my code?
I have come up with the following code to solve caesar.c of pset2. It passes all check50 tests. However, it fails to detect when a string input is not a number. The way I understand it, I have to ...
0
votes
1answer
22 views
Why is my if else statement not working?
Here's my Code:
#include<stdio.h>
#include<cs50.h>
int main (void)
{
string a= get_string("Enter a name\n");
string b= get_string("Enter Class\n");
...
0
votes
1answer
94 views
I don't understand the comments from check50 on my lab 1 submission. could anyone help please?
This is my code
#include <cs50.h>
#include <stdio.h>
int main(void)
{
// TODO: Prompt for start size
int s;
do
{
s= get_int("Start size: ");
}
...
0
votes
1answer
42 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
68 views
Mario less, struggling with nested FOR loop
hello I have got my code to work but don't understand logic, I found a flow cart for how nested for loops work and with that I was able to mix things around until I got it to output correctly but ...
0
votes
1answer
15 views
How can i arrange the output in decending order In this program? [closed]
#include <stdio.h>
int main()
{
int n,i;
printf("Enter a number: ");
scanf("%d",&n);
for (i=0; i<=n; ++i)
{
if (i%(7*13*19)==0)
{
...
0
votes
1answer
18 views
Why is my get_positive_int code not working? (I seem to do everything right!)
Here's my code (written in C), I was trying to program this for a long time, and even when I just tried to copy the code directly from the video lecture, it's wrong! Please help me.
Here's my code:
#...
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 ...
0
votes
1answer
28 views
pset4 recover creates 50 images but bytes don't match up
My code creates the 50 files, all of them starting with the correct JPEG signature, however the rest of the bytes don't match up. In other words, first 4 bytes are correct, the following bytes are ...
