malloc in c 2b 2b

1#include <iostream>
2#include <cstdlib>
3using namespace std;
4
5int main()
6{
7	int *ptr;
8	ptr = (int*) malloc(5*sizeof(int));
9
10	if(!ptr)
11	{
12		cout << "Memory Allocation Failed";
13		exit(1);
14	}
15	cout << "Initializing values..." << endl << endl;
16
17	for (int i=0; i<5; i++)
18	{
19		ptr[i] = i*2+1;
20	}
21	cout << "Initialized values" << endl;
22
23	for (int i=0; i<5; i++)
24	{
25		/* ptr[i] and *(ptr+i) can be used interchangeably */
26		cout << *(ptr+i) << endl;
27	}
28
29	free(ptr);
30	return 0;
31}

1/* malloc example: random string generator*/
2#include <stdio.h>      /* printf, scanf, NULL */
3#include <stdlib.h>     /* malloc, free, rand */
4
5int main ()
6{
7  int i,n;
8  char * buffer;
9
10  printf ("How long do you want the string? ");
11  scanf ("%d", &i);
12
13  buffer = (char*) malloc (i+1);
14  if (buffer==NULL) exit (1);
15
16  for (n=0; n<i; n++)
17    buffer[n]=rand()%26+'a';
18  buffer[i]='\0';
19
20  printf ("Random string: %s\n",buffer);
21  free (buffer);
22
23  return 0;
24}

1int alloc_size = 10;
2int* buffer = (int*) malloc (alloc_size);
3//Allocate memory block which can fit 10 integers 

1void* malloc(size_t size);