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Pointer Notation in C

Joe1903 (33)
How I can Write following code with poiner notation (char *s) instead of char s[ ]?

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#include <stdio.h>

#define LENGTH 80

int main(void)
{
    int c, i, j;
    char s[LENGTH];

    i = 0;
    while ((c = getchar()) != EOF)
    {
        if (c != '\n')
        {
            if (i == LENGTH)
                for (j = 0; j < LENGTH; j++)
                    putchar(s[j]);

            if (i >= LENGTH)
                putchar(c);
            else
                s[i] = c;

            i++;
        }
        else
        {
            if (i > LENGTH)
                putchar('\n');
            i = 0;
        }
    }

    return 0;
}
Last edited on
TheIdeasMan (6782)
Joe1903 (33)
Yes I know but nobody answered.I thought if I create a separate thread it will help.
Joe1903 (33)
Please could someone help me??PLEASE..
Naughty Albatross (1283)
Hi,
Can you explain what is a "pointer notation"?
nuderobmonkey (640)
*(array+index) is the pointer notation of array[index]
I hope this is what you requested.
Joe1903 (33)
Trank you very much.But how I can describe char s[LENGTH] with *.?
Naughty Albatross (1283)
This might be what you need : 
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#include <stdio.h>
#define LENGTH 80
int main(void)
{
    int c, i, j;
    char *s; s = new char[LENGTH];
    i = 0;
    while ((c = getchar()) != EOF)
    {
        if (c != '\n')
        {
            if (i == LENGTH)
                for (j = 0; j < LENGTH; j++)
                    putchar(*(s + j));
            if (i >= LENGTH)
                putchar(c);
            else             *(s + i) = c;
            i++;
        }
        else        {
            if (i > LENGTH)
                putchar('\n');
            i = 0;
        }
    }
    delete [] s;
    return 0;
}
nuderobmonkey (640)
In C there is no way reserving memory at program space other then via:

my_type var_name = my_type[LENGTH]

That line instructs the compiler to reserve a whole array. Instead, a pointer holds just an address, pointing to a part of memory. Therefore, array[index] and *(array+index) are just pointers references to the same part of memory.
Last edited on
Joe1903 (33)
Thank you very much.I will try and let you know.
Joe1903 (33)
What about this one:

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void reverse(char s[])
{
  int i, j;
  char c;

  i = 0;
  while (s[i] != '\0')
    ++i;
  --i;

  if (s[i] == '\n')
    --i;

  j = 0;
  while (j < i)
  {
    c = s[j];
    s[j] = s[i];
    s[i] = c;
    --i;
    ++j;
  }
}
Last edited on
Naughty Albatross (1283)
> What about this one?
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void reverse(char *s)
{
  int i, j;
  char c;
  i = 0;
  while (*(s + i) != '\0')
    ++i;
  --i;
  if (*(s + i) == '\n')
    --i;
  j = 0;
  while (j < i)
  {
    c = *(s + j);
    *(s + j) = *(s + i);
    *(s + i) = c;
    --i;
    ++j;
  }
}
Joe1903 (33)
The one with LENGTH is not working.What can be the cause?
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