What is the difference between malloc and new?

This is the regular question generally you will get in C++ Interviews. Both new and malloc are used to allocate the dynamic memory. malloc is used in C and new is used in C++. And the basci difference is new calls the constructor to allocate the memory whereas malloc() is itself is a function and it wont call the  constructor. Lets see the differences.

malloc:

• This is a function
• It will return the void pointer.
• Need to type cast to the required data type.
• It returns NULL if there is no enough memory.
• It works in C and C++
• need to use free to deallocate the memory
• This cann't be overleaded
• syntax:

               void *malloc(size_t size)

• example:

int *ptr;
ptr = (int *)malloc(10*sizeof(int));  // allocationg 10 bytes of int type
//do something
free(ptr); // deallocating the memory

new:

• new is an operator.
• It calls the constructor while allocating the memory and destructor while deallocating the memory
• It will return required pointer data type
• No need to type cast
• It will return bad exception when there is no enough memory
• It works only in C++
• Need to use delete for deallocating the memory
• its possible to overload the new operator
• Syntax:

            ptr = new typename; 
where ptr is pointer of typename(generally class name).

• example:

int *p;
p = new int; // allocating int datatype
//do something
delete p; // for deallocating the memory