keywords: new, new [], delete, delete []

These keywords are used to dynamically allocate and deallocate memory.

If you allocate memory with new, you MUST deallocate it with delete. Failing to do so can cause one of the worst kinds of bugs, known as memory leaks, and on an Arduino that has bare kilobytes of RAM, a memory leak will cause the Arduino to crash very quickly, and you won’t get a message telling you that it crashed. It will just be in a crashed state, doing nothing at all, until you reset it.

new[] and delete[] are used for allocating and deallocating arrays. Same rules apply with them, just make sure to only use delete[] with new[] and delete with new… mix and match is not a good idea.

Usage:

int *x = new int; 	//make me a new integer;
*x = 5;				//x points to an integer, which is 5.
delete x;			//x points to the same spot, but it has been freed

x = new int[5];		//now x points to an array of five integers

delete [] x;		//x points to the same spot, but all 5 slots have been freed.