Arbitrary-strings using getline

Question

So basically what my program did before i had to change it so that it would accept arbitrary values, was to take x-amount of words and the size of the words would also be arbitrary. (both are user inputted). I did this via a multiArray. Then sorted according to alphabetical-order.

I'm just going to put it out there as my code is shit and I'm very unfamiliar with the usage of arbitrary-strings and pointers. I've read up on it in the manual but the concept needs to sink in a little bit first i believe. Anyhow, I get the error: "Abort trap: 6" when i run the program. Could anyone please help me fix this problem so that i can see how the code would look like if it was actually working, i think that would help me understand both pointers and allocating memory a lot better. Forever in debt if you do.

Current code:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define MAX_LENGTH 10
int main(){ //8

  char *name;
  char tname[] = {0};
  char temp[] = {0};
  int i=0, j=0, n=0;
  ssize_t bytes_read;
  size_t bytes_number;


  printf("Enter the amount of words you want to input: ");
  scanf("%d", &n);
  printf("Enter %d words: ",n);

  bytes_number = MAX_LENGTH;
  name = (char *) malloc (bytes_number+ 1);
  bytes_number = 0;
  bytes_read = getline(&name, &bytes_number, stdin);

  if (bytes_read == -1){
    puts("ERROR!");
    free(name);
  }

  for (i = 0; i < n; i++){
      strcpy(&tname[i], &name[i]);
  }
  for (i = 0; i < n - 1 ; i++){
      for ( j = i + 1; j < n; j++){
          if (strcmp(&name[i], &name[j]) > 0){
              strcpy(temp, &name[i]);
              strcpy(&name[i], &name[j]);
              strcpy(&name[j], temp);
          }
      }
  }
  printf("\n------------------------------------------\n");
  printf("%-3s %4s %11s\n", "Input","|", "Output");
  printf("------------------------------------------\n");
  for (i = 0; i < n; i++)
  {
      printf("%s\t\t%s\n", &tname[i], &name[i]);
  }
  printf("------------------------------------------\n");
  }

Answer 1

This

strcpy(&tname[i], &name[i]);

is completely wrong, if you just want to copy all the characters, then it's just

strcpy(tname, name);

which is equivalent to

for (size_t i = 0 ; name[i] != '\0' ; ++i)
    tname[i] = name[i];

using strcpy(&tname[i], &name[i]) is wrong because it will copy all the bytes from name until '\0' is found, at every loop starting at the i-th character.

But this will fail again because tname is does not have room, it's an array with just one element.

Since you want to sort the strings, you DO NOT NEED TO COPY them. Just swap the pointers. Also

char temp[] = {0};

only allocates 1 character, thus

strcpy(temp, name);

will invoke Undefined Behavior.

Try this, maybe it's what you need

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int
main(void)
{
    char **words;
    char *temp;
    int word_count;
    int actual_count;
    char *word;
    size_t length;
    int result;

    printf("Enter the amount of words you want to input: ");
    if (scanf("%d%*c", &word_count) != 1)
        return -1; // Input error
    printf("Enter '%d' words:\n", word_count);

    words = NULL;
    word = NULL;
    result = -1;
    actual_count = 0;
    length = 0;
    for (int i = 0 ; i < word_count ; ++i)
    {
        char **pointer;

        printf("Word(%d) > ", i + 1);

        if ((length = getline(&word, &length, stdin)) <= 0)
            goto cleanup;
        // Grow the array of words
        pointer = realloc(words, (i + 1) * sizeof(*pointer));
        if (pointer == NULL)
            goto cleanup; // Memory Exhausted
        // Now it's safe to overwrite `words'
        words = pointer;

        words[i] = malloc(length);
        if (words[i] == NULL)
            goto cleanup; // Memory Exhausted
        memcpy(words[i], word, length);
        words[i][length - 1] = '\0'; // Replace '\n' with '\0'
        actual_count += 1;
    }

    printf("Input : ");
    for (int i = 0 ; i < actual_count ; ++i)
        printf("%s\t", words[i]);
    printf("\n");

    for (int i = 0; i < actual_count - 1 ; i++)
    {
        for (int j = i + 1 ; j < actual_count ; ++j)
        {
            if (strcmp(words[i], words[j]) <= 0)
                continue;
            temp = words[i];
            words[i] = words[j];
            words[j] = temp;
        }
    }

    printf("Output: ");
    for (int i = 0 ; i < actual_count ; ++i)
        printf("%s\t", words[i]);
    printf("\n");

    result = 0;
cleanup:
    free(word);
    for (int i = 0; i < actual_count ; i++)
        free(words[i]);
    free(words);

    return result;
}

Note: This would consider an empty word (made completely of white space characters), as a valid word.