What is a tuple, or std::tuple? How can I use a tuple in a C++ compiler? Can I store different types of variables in tuple template?
Table of Contents
What does std::tuple mean to a C++ compiler?
The tuple ( std::tuple) is a class template a fixed-size collection of different types of values like floats, integers, texts, etc. In another term tuple stores the different types of the elements, it also supports empty lists. This template is available since C++11 and improved in C++20 standards.
std::tuple is a generalization of std::pair. The destructor of tuple is trivial if std::is_trivially_destructible<type>::value is set to true for every type in Types.
What is the syntax for the C++ std::tuple?
Here is the syntax of std::tuple:
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template< class... Types > class tuple; |
Is there a std::tuple example I can use in my Windows C++ compiler?
Here is a example to define different types of members in a my_tuple,
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#include <iostream> #include <tchar.h> #include <tuple> int main() { std::tuple my_tuple { "text one", 1, 2.22, "text two", 9.81 , "text three"}; return 0; } |
As in this example we can print out each element by using std::get< > as given example below,
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#include <iostream> #include <tchar.h> #include <tuple> int main() { std::tuple my_tuple { "text one", 1, 2.22, "text two", 9.81 , "text three"}; std::cout << std::get<0>( my_tuple ) << std::endl; std::cout << std::get<1>( my_tuple ) << std::endl; std::cout << std::get<2>( my_tuple ) << std::endl; std::cout << std::get<3>( my_tuple ) << std::endl; std::cout << std::get<4>( my_tuple ) << std::endl; getchar(); return 0; } |
And the output will be,
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text one 1 2.22 text two 9.81 |
How to iterate std::tuple?
Interestingly std::tuple has no begin() and end() iterator parameters, that means you cannot iterate in a C++ compiler of version C++17 and before. To Iterate on std::tuple you can use std::apply as below,
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#include <iostream> #include <tchar.h> #include <tuple> template <typename T> void print_tuple(const T& tup) { std::apply( [](auto&&... params) { ( ( std::cout << params << std::endl ), ... ); }, tup ); } int main() { std::tuple my_tuple { "text one", 1, 2.22, "text two", 9.81 , "text three"}; print_tuple(my_tuple); getchar(); return 0; } |
And the output will be,
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text one 1 2.22 text two 9.81 |
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