malloc() vs new (original) (raw)

Last Updated : 5 Jun, 2026

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 header file.
• Allocates memory but does not initialize it.
• Does not call constructors for objects.

Syntax

pointer = (data_type*)malloc(size_in_bytes);

C++ `

#include #include using namespace std;

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

*ptr = 100;

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

free(ptr);

return 0;

}

`

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;

C++ `

#include using namespace std;

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

*ptr = 100;

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

delete ptr;

return 0;

}

`

malloc() vs new