map<string>, vector<string>> myMap

[Amiplus]

Thank you for the numerous examples.

About the

for( const auto& str : query( mmap, key, attribute ) ) std::cout << std::quoted(str) << ' ' ;

how the iteration knows that the cycle is end?

[JLBorges]

A range-based for loop iterates over a 'range' -
from the begin() of the range up to, not including, the end() of the range.

http://www.stroustrup.com/C++11FAQ.html#for
http://en.cppreference.com/w/cpp/language/range-for

[Amiplus]

Thank you.


In this loop i'm trying to do some conditional check:

for( const auto& str : query( mmap, key, attribute ) ) std::cout << std::quoted(str) << ' ' ;

example

for( const auto& str : query( mmap, key, attribute ) ) {

if ((str)=="solar system" {

     std::cout << "Pluto is part of our solar system" << endl;
}
}

but sometimes i get an error. The program crash and i get Process returned 255 (0xFF).

I think it's related to something out of bound. Why?

[JLBorges]

The lifetime of a temporary used as the range-expression is extended till the end of the loop.

Nevertheless, try these:

Do you still get the same error if you write:

for( /*const auto&*/ auto str : query( mmap, key, attribute ) ) {

     if ((str)=="solar system" {

         std::cout << "Pluto is part of our solar system" << endl;
     }
}

Do you get the same error even if you write:

const auto /*&*/ range = query( mmap, key, attribute ) ; // *** EDIT 
for( /*const auto&*/ auto str : range ) {

     if ((str)=="solar system" {

         std::cout << "Pluto is part of our solar system" << endl;
     }
}

[Amiplus]

Sorry for the late replay.

Seems that the mentioned routine was not involved.
I have to investigate in other direction.

Thank you, however.