malloc() vs new

Following are the differences between malloc() and operator new.:

1. Calling Constructors: new calls constructors, while malloc() does not. In fact primitive data types (char, int, float.. etc) can also be initialized with new. For example, below program prints 10.
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   #include<iostream> using namespace std; int main() {     // Initialization with new()     int *n = new int(10);      cout << *n;     getchar();     return 0; }

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   Output:

   10
   

2. operator vs function: new is an operator, while malloc() is a function.
3. return type: new returns exact data type, while malloc() returns void *.
4. Failure Condition: On failure, malloc() returns NULL where as new throws bad_alloc exception.
5. Memory: In case of new, memory is allocated from free store where as in malloc() memory allocation is done from heap.
6. Overriding: We are allowed to override new operator where as we can not override the malloc() function legally.
7. Size: Required size of memory is calculated by compiler for new, where as we have to manually calculate size for malloc().
8. Buffer Size: malloc() allows to change the size of buffer using realloc() while new doesn’t

new	malloc
calls constructor	doesnot calls constructors
It is an operator	It is a function
Returns exact data type	Returns void *
on failure, Throws	On failure, returns NULL
Memory allocated from free store	Memory allocated from heap
can be overridden	cannot be overridden
size is calculated by compiler	size is calculated manually

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