[Antonella Ritorto]

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Thanks a lot Hans, Diana, and Rainer for the detailed explanation and examples.

[Antonella Ritorto]

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Thanks you very much Driton and Rainer. I’m also using compiler explorer, but maybe I’m not choosing correctly the settings and that’s why I get other error messages. Thanks again!

[Antonella Ritorto]

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Many thanks for the example. It gives me a better understanding. So local variable var is captured and returned by the lambda-function returned when calling makeLambda(), but at the same time cannot go out of its scope. I hope I get it. Thanks again!

[Antonella Ritorto]

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Thanks, Dominik. I see the point now. Thanks for the reference to c++ representations!

[Antonella Ritorto]

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Thanks, Kuci. Indeed, I used CppInsights. I understood it’s related to those implicit conversations but wanted to know why ‘a’ turns 97, instead of some other value. Probably it’s not as important as understanding how auto works with a template function, in the return type. Thanks again!

[Antonella Ritorto]

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Thank you very much for your response Kuci. May I ask what do you mean with lifetime of the object/variable you are returning the const& from? (I’m a beginner). Could it be that if I have something like:

 

std::function<const std::string&(const std::string&)> func = 
  [](const std::string& a){return a;};

void print{
 auto myValue = func(const std::string& a);
}
// myValue is dead here, isn't it? but any other local variable would be also dead...

 

Many thanks in advance!

[Antonella Ritorto]

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Thank you very much. I double-checked again, and now I do not get any error message. I used the command line g++ file.cpp -o file. It’s working now, both options: const double& n, or just double n.

Thanks again!

[Antonella Ritorto]

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Thanks! That’s the correct code. The incorrect one would be to replace the piece:

friend MyDistance operator *(double m, const MyDistance& b){
return MyDistance(m*b.m);
}

by (my incorrect attempt):

friend MyDistance operator *(double n, const MyDistance& b){ // const double& n
return MyDistance(n*b.m);
}

 

[Antonella Ritorto]

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Thank you very much to both Rainer and Kuci.

[Antonella Ritorto]

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Hi Diana! Nice to meet you and to hear we have kind of the same experience! Spanish-speakers women in Math/Industry :)

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