Following are the differences between malloc() and operator new.:
- 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.
CPP
#include<iostream>using namespace std;int main(){ // Initialization with new() int *n = new int(10); cout << *n; getchar(); return 0;} |
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. Size: Required size of memory is calculated by compiler for new, where as we have to manually calculate size for malloc().
7. Buffer Size: malloc() allows to change the size of buffer using realloc() while new doesn’t
| new | malloc |
|---|---|
| calls constructor | does not calls constructors |
| It is an operator | It is a function |
| Returns exact data type | Returns void * |
| on failure, Throws | On failure, returns NULL |
| size is calculated by compiler | size is calculated manually |
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