malloc() vs new

malloc() and new are used for dynamic memory allocation in C++, allowing memory to be allocated during program execution. Although both allocate memory from the heap, they differ in functionality, type safety, and object handling.

• malloc() is a C library function, while new is a C++ operator.
• new is generally preferred in C++ because it supports constructors and type safety.

malloc()

malloc() (Memory Allocation) is a standard C library function used to allocate a specified amount of memory at runtime. It allocates raw memory and returns a pointer to the allocated block.

• Defined in the <cstdlib> header file.
• Allocates memory but does not initialize it.
• Does not call constructors for objects.

Syntax

pointer = (data_type*)malloc(size_in_bytes);

#include <iostream>
#include <cstdlib>
using namespace std;

int main() {
    int* ptr = (int*)malloc(sizeof(int));

    *ptr = 100;

    cout << "Value: " << *ptr;

    free(ptr);

    return 0;
}

Value: 100

new Operator

The new operator is a C++ feature used to dynamically allocate memory for variables and objects. It automatically returns the correct pointer type and invokes constructors when creating objects.

• No explicit type casting is required.
• Calls constructors for objects automatically.
• Memory is released using the delete operator.

Syntax

pointer = new data_type;

#include <iostream>
using namespace std;

int main() {
    int* ptr = new int;

    *ptr = 100;

    cout << "Value: " << *ptr;

    delete ptr;

    return 0;
}

Value: 100

malloc() vs new