dynamic memory allocation

1int *array = malloc(10 * sizeof(int));

1// Use malloc to allocate memory
2ptr = (castType*) malloc(size);
3int *exampl = (int*) malloc(sizeof(int));
4// Use calloc to allocate and inizialize n contiguous blocks of memory
5ptr = (castType*) calloc(n, size);
6char *exampl = (char*) calloc(20, sizeof(char));

1#include <stdlib.h>
2
3void *malloc(size_t size);
4
5void exemple(void)
6{
7  char *string;
8  
9  string = malloc(sizeof(char) * 5);
10  if (string == NULL)
11    return;
12  string[0] = 'H';
13  string[1] = 'e';
14  string[2] = 'y';
15  string[3] = '!';
16  string[4] = '\0';
17  printf("%s\n", string);
18  free(string);
19}
20
21/// output : "Hey!"

1
2// declare a pointer variable to point to allocated heap space
3int    *p_array;
4double *d_array;
5
6// call malloc to allocate that appropriate number of bytes for the array
7
8p_array = (int *)malloc(sizeof(int)*50);      // allocate 50 ints
9d_array = (int *)malloc(sizeof(double)*100);  // allocate 100 doubles
10
11
12// use [] notation to access array buckets 
13// (THIS IS THE PREFERED WAY TO DO IT)
14for(i=0; i < 50; i++) {
15  p_array[i] = 0;
16}
17
18// you can use pointer arithmetic (but in general don't)
19double *dptr = d_array;    // the value of d_array is equivalent to &(d_array[0])
20for(i=0; i < 50; i++) {
21  *dptr = 0;
22  dptr++;
23}
24

1int *p = new int; // request memory
2*p = 5; // store value
3
4cout << *p << endl; // Output is 5
5
6delete p; // free up the memory
7
8cout << *p << endl; // Output is 0

1int* a =(int*)malloc(sizeof(int))