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C ++: print string vector returned by function

So essentially I have a private std::vector<std::string> alloc

in class A

that has some manipulation etc. done on it by a public method std::vector<std::string> allocMethod()

and that method then executes return alloc

. The method is called inclass B

Q class B

I want to print the return value allocMethod

, i.e. vector alloc

. This is what I have

std::cout << A.allocMethod();

I know it is usually possible to use some kind of interpreter and loop to print the vector, but I don't think I can do that as this is the return value of the functions, which is not actually printed by the vector.

Note. I reeaaally don't want to just print the vector into class A

.

Is there a way to output the result std::vector<string>

as shown above?

+3


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3 answers


"Note: I don't want to just print the vector in class A."

As you want to reuse this, it may be wise to provide an appropriate overload of the output statement for std::vector<std::string> 

std::ostream& operator<<(std::ostream& os,const std::vector<std::string>>& vs) {
    for (const auto& s : vs) {
        os << s << " ";
    }
    return os;
}

This should let you just call



std::cout << A.allocMethod();

You can even try more general overload

template<typename T>
std::ostream& operator<<(std::ostream& os,const std::vector<T>>& vs) {
    for (const auto& s : vs) {
        os << s << " ";
    }
    return os;
}
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Contrary to your belief, you can print out a vector by iterating over it, although this is a temporary C ++ 11 use for a loop:



for (const auto& i : A.allocMethod())
    std::cout << i << '\n';
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You can just store the return value and then loop over it. Like this:

std::vector<std::string> result = allocMethod();
for (std::size_t i = 0; i < result.size(); ++i)
{
    std::cout << result[i];
}
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