When will stack undwinding take place?

stackunwinding.cpp

// When will the destructor of class C get called?
// 1. If we call exit?
// 2. If we call abort?
// 3. If we throw an exception?
// 4. If we throw an exception that won't be caught (comment out the try-catch statement) 
//    and thus invokes the terminate() handler?

#include <cstdlib>
#include <iostream>

using namespace std;

class C {
public:
    C()  { cout << "ctor\n"; }
    ~C() { cout << "dtor\n"; }
};

int f() {
    C c;
    // exit(0);     // 1.
    // abort();     // 2.
    // throw 42;    // 3.
}

int main() {
    try {           // 4.
        f();
    } catch (...) {
    }
}