Suppose that a function normally allocates memory for an object, uses it, and then deallocates the memory. But if the function exits before reaching the end, either because of a return statement or an exception, it must still not exit without deallocating the memory:

void foo(int n){    my_class* ptr = new my_class;    try {        ptr->process(n); // may throw exception    } catch (...) {        delete ptr;        throw;    }    delete ptr;}

The C++ standard libary provides an automatic pointer type, auto_ptr, which you can use by including . An auto_ptr is constructed using a pointer. You can then use and dereference auto_ptr as if it were a pointer. When an auto_ptr goes out of scope, the destructor frees the memory automatically. The example above may thus be simplified to:

#include void foo(int n){    std::auto_ptr ptr(new my_class);    ptr->process(n);}