Questions tagged [hash-function]

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My check function in speller isn't working

I have implemented everything else but this check function when I try to test it it seems like the the check function isn't working, because the no. of misspelled words is the same as the no. in text.....
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2answers
6k views

PSET5 Speller hash function

I have been working on the speller problem in pset5 for a while now, and I am not able to figure out the problem in my hash function: unsigned int hash(const char* word) { int M = 1000000001; ...
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Speller - Compiles but Doesn't Hit Criteria for Completion

I've been having a lot of trouble with Speller. This compiles but almost all the criteria are red, for example it doesn't basic words properly, doesn't handle 1 char words or long words, etc. I'm not ...
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1answer
52 views

Hash Function in Speller - Use of Undeclared Identifier Error

I'm stuck on the speller assignment but it feels like the smallest thing to be stuck on....in my hash function I keep getting "use of undeclared identifier" for n and i. Usually if this ...
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0answers
20 views

trouble loading dictionary

my load function seems to only load two words and all words are coming back misspelled. I don't know if the problem is with my load function or the hash function. I've gone over the load function ...
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3answers
307 views

PSET 5 Hash help

I started my load function without looking at any reference code (first time starting a pset this way) to give me an idea on how to implement my own version. I was mostly confident until I reached the ...
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113 views

PSET 5 SPELLER - HELP!

i'm not sure why this happens when I execute the code. The program seems to never end as if it's running an infinite loop. When I run valgrind on it misspelled words keep spewing out and it gives me a ...
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1answer
60 views

Pset5 Speller: every word in text reported as misspelled

Code compiles, dictionary loads and unloads, word count works and hash function seems to work. However, the results show that every word in the text is misspelled. I’ve spent 3 weeks tweaking the code ...
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2answers
197 views

Pset5 speller - load clang error (linker command error) and multiple definition

I typed make speller and clang produces the output below. I'm really not sure how to resolve this. I thought that it might be saying that I defined the hash function twice but I don't think I have. ...
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0answers
149 views

Shows double free or corruption (fasttop)

// Implements a dictionary's functionality #include <stdbool.h> #include <stdio.h> #include <string.h> #include <stdlib.h> #include "dictionary.h" // Represents a node in a ...
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93 views

PSET5 Valgrind Problem!

I have my code semi working (it passes most of the check50) except Valgrind keeps reporting 'Invalid read of size 1' . Here is a screenshot of the error message: . I used the djb2 hash function. ...
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1answer
366 views

Speller Valgrind leaks bytes + error: munmap_chunk(): invalid pointer error in C

Check50 gives me the munmap_chunk: invalid pointer - it seems I am not copying something right with strcpy. Valgrind gives me: LEAK SUMMARY: still reachable: 608 bytes in 2 blocks ==2864== 56 bytes ...
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1answer
631 views

Is this hash function valid?

I just wonder if this hash function is correct? I was thinking that the index cannot be above 26 as it would look for memory outside the array, and would probably cause a segmentation fault. Therefore ...
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1answer
109 views

PSET4 free on malloc in hash function

I'm trying to improve my hash function in Speller and I'm having trouble freeing allocated memmory. I'm getting * Error in `./speller': free(): invalid pointer: 0x0000000001a02252 * Aborted I know ...
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1answer
70 views

pset5 speller program doesn't display benchmarks

When I ran my code through the compiler, it displays all the misspelled word correctly as per the staff solution. However, the program does not end after displaying all the misspelled words and it ...
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1answer
1k views

PSET5: Hash function returning collisions

Looking for advice on hash functions and strings. For PSET5, I decided to implement a trie but instead of storing [a - z] in each node, only storing [0 - 9]. For this to work, I hashed the words and ...
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1answer
117 views

pset5 load null pointer issue

Working through the load portion of pset5. Everything compiles, but when I run valgrind it looks as if nothing is actually loading in, with the error of "null pointer passed as argument 1, which is ...
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1answer
321 views

Check function too slow in pset5

I've completed "Speller" successfully, but have been trying to optimise it as the run time for "check" is significantly longer than the staff solution. I suspect the reason is that I don't have ...
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1answer
235 views

Pset 5 Speller - Undefined reference to hashValue in load and check

When I compile and run speller, I get the following from the terminal: dictionary.o: In function check': /home/ubuntu/workspace/pset5/speller/dictionary.c:51: undefined reference tohashValue' ...
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3answers
55 views

16 letter words show up as misspelled from Pset5

I found this great hash function. But I noticed something very weird during pset5. When I am testing my program by putting the outputs of my program and the staff solution into student.txt and staff....
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1answer
105 views

PSET5: Hash function and code not handling possessives and substrings

I am having a lot of problems with pset5. I have identified more than one issue with the code but I don’t know how to fix the issues. The first is from my hash function, which is featured below and I ...
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1answer
560 views

Why does this hash function fail?

unsigned int hash(const char *str) { unsigned int hash = 5381; int c; int i; size_t k= strlen(str)*1; char *str2=malloc(k+1); strcpy(str2,str); for(i=0;i<strlen(str);i++...
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1answer
581 views

Segmentation fault occurs if I delete an unused global variable in Pset5

It looks I have broken C while working on Pset5, I mean, I don't understand a bit why this happens. First, I completed the problem with the simplest of hash functions which just processes the first ...
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2answers
1k views

pset5 load, hash function , lost :(

i am a beginner and wanted to solve the pset with hashfunction and than a linked list. I wanted to start out with the simplest way i can thought of. One bucket for every letter in the alphabet. Here ...
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1answer
947 views

Problems with hash function in pset5

I'm using a hash function I found online that's meant to be quick but it's throwing an error that I don't understand (and as I've cut and paste it, I don't get what the issue can be?). Everything else ...
1
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1answer
747 views

Pset6: Is it possible implement a 3D Hash table Matrix?

It might be too early on for me to ask questions in this problem set, as I am just getting started with load. I was looking up Hash Functions, and they look a little cryptic to me. Is it possible to ...