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()
{
int *n = new int (10);
cout << *n;
getchar ();
return 0;
}
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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() |
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calls constructor | does not calls constructors |
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It is an operator | It is a function |
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Returns exact data type | Returns void * |
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on failure, Throws bad_alloc exception | On failure, returns NULL |
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size is calculated by compiler | size is calculated manually |
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