both malloc and new functions are used for dynamic memory
allocations and the basic difference is: malloc requires a
special "typecasting" when it allocates memory for eg. if
the pointer used is the char pointer then after the
processor allocates memory then this allocated memory needs
to be typecasted to char pointer i.e (char*).but new does
not requires any typecasting. Also, free is the keyword used
to free the memory while using malloc and delete the keyword
to free memory while using new, otherwise this will lead the
memory leak.

The difference is the invocation of constructor: malloc 
does not do it.

new automatically calls the constructor while malloc() 
dosen't., also new being an operator, it can be overloaded.

since malloc returns a void pointer it is necessary to 
explicitly typecast it into an appropriate type of pointer. 
This gets completely avoided when we are using new operator.