Default string arguments

Question

myPreciousFunction(std::string s1 = "", std::string s2 = "")
{
}

int main()
{
    myPreciousFunction();
}

Can i make the arguments look more pretty? I want there to be empty strings if no arguments were supplied.

Answer 1

you may consider this:

myPreciousFunction(std::string s1 = std::string(), std::string s2 = std::string())
{
}

But it doesn't really look prettier.

Also, if you're passing strings, you might want to pass them as const&:

myPreciousFunction(const std::string& s1, const std::string& s2)
{
}

This is a standard way to avoid coping the data around.

Answer 2

There is actually another solution.

const std::string empty = std::string();

myPreciousFunction( const std::string &s1 = empty, const std::string &s2 = empty)

This has the advantage of avoiding construction of temporary objects.

Answer 3

You could use a braced initialisation:

myPreciousFunction(const std::string& s1 = {}, const std::string& s2 = {})
{
}