In c++ what does a tilde "~" before a function name signify?
template <class T>
class Stack
{
public:
Stack(int = 10) ;
~Stack() { delete [] stackPtr ; } //<--- What does the "~" signify?
int push(const T&);
int pop(T&) ;
int isEmpty()const { return top == -1 ; }
int isFull() const { return top == size - 1 ; }
private:
int size ;
int top ;
T* stackPtr ;
} ;
It's the destructor, it destroys the instance, frees up memory, etc. etc.
Here's a description from ibm.com:
Destructors are usually used to deallocate memory and do other cleanup for a class object and its class members when the object is destroyed. A destructor is called for a class object when that object passes out of scope or is explicitly deleted.
See https://www.ibm.com/support/knowledgecenter/en/ssw_ibm_i_74/rzarg/cplr380.htm
As others have noted, in the instance you are asking about it is the destructor for class Stack
.
But taking your question exactly as it appears in the title:
In c++ what does a tilde “~” before a function name signify?
there is another situation. In any context except immediately before the name of a class (which is the destructor context), ~
is the one's complement (or bitwise not) operator. To be sure it does not come up very often, but you can imagine a case like
if (~getMask()) { ...
which looks similar, but has a very different meaning.