删除/删除向量项目的最有效/最快方法

Question

There are several ways to delete/remove items of a vector.

I have a vector of pointers and I need to delete all of them on the deconstructor of the class.

What is the most efficient/fastest way or even safest way?

// 1º
std::for_each(vector.begin(), vector.end(), [] (Object * object) {
    delete object;
});

// 2º
for (int i = 0; i < vector.size(); ++i)
{
    delete vector[i];
}

// 3º
for (auto current = vector.begin(); current != vector.end(); ++current){
    delete (* current);
}

Answer 1

The safest way would be to use either std::vector<std::unique_ptr<Object>> or std::vector<std::shared_ptr<Object>> depending on the lifetime semantics you need for the Object instances.

Either way, you wouldn't need to do anything in the destructor; the vector's destructor will destruct all of the smart pointer instances. In turn, they would automatically delete the Object instances according to their particular semantics: unique_ptr would delete them immediately, while shared_ptr would delete them as soon as no other shared_ptr s point to that object.

It's very unlikely that there will be a faster way either, assuming that you need to store pointers. (If you don't need polymorphism, then you could just use std::vector<Object> which has one less level of indirection.)