In C++, we can use the **`calloc()` function** to allocate a block of memory. This allocated memory can be used for an `array` of objects, and all the `bits` are initialized to `zero`. 

# Syntax

    void* calloc(size_t num, size_t size);

---
## `num`
This represents the *_number of elements_* for which the memory block is allocated. It is an unsigned integral value.

## `size`

This represents the *_size of each element_* in the allocated memory block in `bytes`. It is an unsigned integral value.

> **`size_t`** is an unsigned integral type.

# Return value

The method `calloc()` returns the following cases:

- A pointer to the first byte of the allocated memory block if allocation is successful.

- A null pointer if allocation is failed.

> `calloc()` returns `void`. In order to convert it into other data type, we use typecasting.

# Required headers

``` c++
#include <cstdlib>
```

//Including headers
#include <cstdlib>
#include <iostream>
using namespace std;

int main() {

   //Allocating memory block
   int* ptr = (int*)calloc(10, sizeof(int));
   
   //Checking for failure
   if (!ptr) {
      cout << "Failed to allocated memory\n";
      exit(1);
   }

   //Initializing allocated memory
   for (int i = 0; i < 10; i++) {
      ptr[i] = i;
   }

   //Printing allocated memory
   for (int j = 0; j < 10; j++) {
      cout << *(ptr + j) << endl;
   }

   //ptr[i] and *(ptr+i) are same

   //Deallocating allocated memory
   free(ptr);

   return 0;
}

How to use calloc() in C++

Allocate zero-initialized memory for arrays in C++ using `calloc(num, size)`; returns a pointer or NULL.

How to use calloc() in C++

Syntax

num

size

Return value

Required headers

Code

`num`

`size`