Thread: Performing individual actions on chars in an array.

Well it depends. If you treat your array as a string(meaning that you always have \0 at the end) then you can just initialize your character to the start of the array, loop until you reach \0, increase the index where you are taking the character from. This can easily be done in a for loop.

Then depending on what you decide to do with that character you can add it to your new array.

The easiest way would probably be to create a second array that you can put the newly ordered chars into. The distinction between character array and string is important, and I'm not quite clear by your post which one you're working. The difference is, a string will definitely have a terminating '\0' character, but a character array might not.

Assuming you're dealing with a string, you might do something like this:

Code:

char *dostuff(char *original_string)
{
  char *new_string = malloc(strlen(str) + 1);
  int i;

  for(i = 0;original_string[i] != '\0';++i)
  {
    char ch = original_string[i];
    // "Perform some actions" here
    new_string[some_index] = ch;
  }
  return new_string;
}

Make sure you free() your memory when you're done with it and be sure the new string is terminated with a '\0'.

Originally Posted by itsme86

The easiest way would probably be to create a second array that you can put the newly ordered chars into. The distinction between character array and string is important, and I'm not quite clear by your post which one you're working. The difference is, a string will definitely have a terminating '\0' character, but a character array might not.

Assuming you're dealing with a string, you might do something like this:

Code:

char *dostuff(char *original_string)
{
  char *new_string = malloc(strlen(str) + 1);
  int i;

  for(i = 0;original_string[i] != '\0';++i)
  {
    char ch = original_string[i];
    // "Perform some actions" here
    new_string[some_index] = ch;
  }
  return new_string;
}

Make sure you free() your memory when you're done with it and be sure the new string is terminated with a '\0'.

Thanks, yeah I'm using a string I think. Now I just have to work out what on earth that piece of code means. I'm only a beginner to the entire of programming

Could you explain what the 'char *new_string = malloc(strlen(str) + 1);' section does? I get the 'for' loop as it pulls each char in order (I'll be converting them to their ASCII values). Then I guess the new_string[index]=ch will add the character back into the new array? I'm confused about exactly how that bit works.

Originally Posted by frankchester

Thanks, yeah I'm using a string I think. Now I just have to work out what on earth that piece of code means. I'm only a beginner to the entire of programming

Could you explain what the 'char *new_string = malloc(strlen(str) + 1);' section does? I get the 'for' loop as it pulls each char in order (I'll be converting them to their ASCII values). Then I guess the new_string[index]=ch will add the character back into the new array? I'm confused about exactly how that bit works.

The malloc allocates memory dynamically for a string of length str + 1(to store the \0) and then returns a pointer to that data. So now, you have new_string pointing to that memory location where you will have your string. free(new_string) will do the exact opposite, meaning it will free the memory allocated once you are done using it.