i have a problem with strcat into 2d array in c - c

Question

im trying to add words from a file into a 2d array , the problem is that after the 7th word , the words start to shape up wierdly , does anyone knows that might cause this?
void count_words(WordCount **wclist, FILE *infile)
{
int num_words = 0;
char ch;
int k=0;
char **pook;
int flagA=0;
pook = malloc(4096*sizeof(char*));//creates a 2d array for every word from the file
for(int i = 0 ; i <4096 ; i++)
{
pook[i] = malloc(50 * sizeof(char*));
}
while((ch=fgetc(infile))!=EOF)
{
ch=tolower(ch);
if(flagA==0)
{
if(isalpha(ch)!=0)
{
num_words++;
flagA=1;
strcat(pook[k]+0, &ch);
}
}
else
{
if(isalpha(ch)!=0)
{
strcat(pook[k]+0, &ch);
}
else
{
flagA = 0;
k++;
}
}
}
for(int i =0 ; i < num_words ;i++)
{
printf("%s\n",pook[i]);
add_word(wclist , pook[i]);
}
}
the input :
input is text file that contains :
ilona.txt
main.c
makefile
wc_sort.o
word_count.c
word_count.h
words
this is how the output should look like :
ilona
txt
main
c
makefile
wc
sort
o
word
count
c
word
count
h
words
this is how the output realy is :
the output is :
ilona
txt
main
c
makefile
wc
sort
o
w o r d
c
o
u
n
t
c
w
o
r
d
t
h
words
*/

Answer 1

So your code has several mistakes, and I'm sure that as you will gain experience, your code will be less messy.
Previous comments have pointed to some of the bugs, so I'll just list them by order:
When you use 'malloc', it doesn't reset the values in the memory cells, so either you do it yourself, or as I suggest, just use 'calloc' - it's a better habit IMO.
You should check that the pointer you allocated memory to, hasn't received a NULL value (because the allocation has failed).
You first allocate memory for the pointers to the character arrays (AKA the number of strings), then allocate memory for the number of characters for each string). Notice that you have a mistake: pook[i] = malloc(50 * sizeof(char*));. This should be pook[i] = malloc(50 * sizeof(char)); because the second allocation is for characters and not pointers to characters.
Though the statement strcat(pook[k]+0, &ch); should be okay since &ch is a pointer to a character like declaring an array and using the pointer to the array, though note yourself that most compilers probably won't let you do that; In fact, I tried compiling your code in VS 2019, and it didn't even let me build it because strcat is an un-safe function.
In pook[k]+0, the zero is irrelevant, and can cause problems to the compilation as it sometimes might identify it as an arithmetic argument, instead of a pointer.
Also, IMO you should add comments before uploading your code, so It would be easier for other people to understand your code and help you find the solution faster, saving you time. Also, it's a must-do habit because you almost always will show other people your code, and even help you if you get lost in your own code.
My version of what you tried to do is the following:
void count_words (FILE* infile)
{
char** pook;
pook = calloc(4096,sizeof(char*)); // Allocate the number of strings
for (int i = 0; i < 4096; i++)
{
pook[i] = calloc(50, sizeof(char)); // Allocate the number of characters for each string
}
int num_words = 0, letter = 0; // Initialize a counter for the amount of words and letters
int flag = 0; // Initialize a flag that represents if we are currently in a word or not.
char ch; // A temp character
while ((ch = fgetc(infile)) != EOF)
{
if (isalpha(ch) == 0 && flag == 0) // If the current character isn't a letter, and we didn't start to read a word:
continue;
else if (isalpha(ch) == 0 && flag == 1) // If the current character isn't a letter, and we finished to read a word:
{
++num_words; // Because we finished reading a new word
flag = 0; // Because we're not in a word anymore
letter = 0; // Same as above
}
else if (isalpha(ch) != 0 && flag == 0) // If this is the first letter in the current word:
{
pook[num_words][letter] = ch; // Insert the value of the current character
++letter; // Advance to the next letter of pook[num_words]
flag = 1; // Because we're currently in a word
}
else if (isalpha(ch) != 0 && flag == 1) // If this is not the first letter of the current word:
{
pook[num_words][letter] = ch; // Insert the value of the current character
++letter; // Advance to the next letter of pook[num_words]
}
}
if (flag == 1) // If the last character before the EOF is still part of the word, we need to increment the num of words.
++num_words;
for (int i = 0; i < num_words; i++)
{
printf("%s\n", pook[i]);
}
}
The output is the following:
ilona
txt
main
c
makefile
wc
sort
o
word
count
c
word
count
h
words
Hope I helped,
Good luck!