C++ 用于向量中的结构访问索引或使用引用代替值

Question

I assume that if I ve got, for example:

vector<string> myVector;
myVector.push_back("Camel");
myVector.push_back("is");
myVector.push_back("a");
myVector.push_back("noble");
myVector.push_back("animal");

And I do:

for (string val : myVector){
    val = "empty";
}

It does not replace value in vector since it has copied content to a new string.

I assume I can do

for (int i=0; i<myVector.size(); i++) {
    myVector[i] = "empty";
}

It will perform the behaviour.

But well. My question is:

There exist any other structure similar to first case where I can say "Pick the reference of the value in the vector instead of you copy value to a new variable" then I can directly affect to vector values instead and having the for (class value : vector) typing model?

Or Best practices for the example without use any of the cases I mentioned? Iterator?

Answer 1

Declare your range based for loop to initialize a reference to each item:

for (string& val : myVector){
    val = "empty";
}

Now the vector's items are modified in-place. The type of the "item" can be anything for which...

<item-type> declarator = *itr;

... is valid when itr is an iterator of the container.