Answers for "how to use malloc"

malloc in c

#include <stdlib.h>

void *malloc(size_t size);

void exemple(void)
{
  char *string;
  
  string = malloc(sizeof(char) * 5);
  if (string == NULL)
    return;
  string[0] = 'H';
  string[1] = 'e';
  string[2] = 'y';
  string[3] = '!';
  string[4] = '';
  printf("%sn", string);
  free(string);
}

/// output : "Hey!"

malloc() in c and c++

/* malloc example: random string generator*/
#include <stdio.h>      /* printf, scanf, NULL */
#include <stdlib.h>     /* malloc, free, rand */

int main ()
{
  int i,n;
  char * buffer;

  printf ("How long do you want the string? ");
  scanf ("%d", &i);

  buffer = (char*) malloc (i+1);
  if (buffer==NULL) exit (1);

  for (n=0; n<i; n++)
    buffer[n]=rand()%26+'a';
  buffer[i]='';

  printf ("Random string: %sn",buffer);
  free (buffer);

  return 0;
}

Malloc

ptr = malloc(size); //You dont need to cast

what is the use of malloc in c

In C, the library function malloc is used to allocate a block of memory on the heap. The program accesses this block of memory via a pointer that malloc returns. When the memory is no longer needed, the pointer is passed to free which deallocates the memory so that it can be used for other purposes.

malloc c++ program

void* malloc(size_t size);