CPP

Pointers vs References

References are essentially pointers in disguise. Internally the same thing happens, it's just easier to write and read the code.

int a;
int& ref = a; // must be initialized to point to an existing variable
int& ref; 	  // is invalid

Structures vs Classes

Just one technical difference, default visibility of class is private while it is public for struct. Struct exists for backward compatibility with C. Generally we use structures to store only data and don't add function and inheritence.

To or not to use new

Allocating memory isn't really a difference, both of the following allocate memory

int* a = new int(5);
int a = 5;

When we use new, the memory isn't cleared until we call delete. So it's useful when we want to return a pointer to a local variable as shown below:

int* get_num()
{
	int* a = new int(5);
	*a *= 100;
	return a;

	// following won't work
	// int a = 5;
	// return &a;
}

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