Problem with malloc?

Question

Hello, I use malloc () to create such a buffer, where buffer is char *

buffer = (char*)malloc(chunksize+1);
  for (k = 0; k < chunksize; k++) {
    buffer[k] = (char) (j+k);
  }

however, in the debugger I see a buffer [3], for example, it is char i, but the buffer is empty (many spaces). But the second time I write the material in the buffer after the free (buffer), it shows the contents that I wrote for the first time, and overwrites it. Can someone tell me why? Thank!

Answer 1

Perhaps the problem is that you are trying to print a buffer charusing printfor equivalent? You are lacking

buffer[chunksize] = 0;

Thus, your buffer is not terminated. It may have something behind, for example '\r'.

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Answer 2

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Answer 3

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

int main ()
{
  const size_t chunksize = 15;
  size_t k;
  char *buffer;

  buffer = malloc (chunksize + 1);
  memset (buffer, 0, chunksize + 1);

  for (k = 0; k < chunksize; ++k)
    {
      buffer[k] = '0' + (char)k + 49;
    }

  for (k = 0; k < chunksize; ++k)
    {
      printf ("%lu = %c\n", k, buffer[k]);
    }

  free (buffer);

  return 0;
}

:

0 = a
1 = b
2 = c
3 = d
4 = e
5 = f
6 = g
7 = h
8 = i
9 = j
10 = k
11 = l
12 = m
13 = n
14 = o