Using 'auto' type deduction - how to find out what type the compiler deduced?

Question

How can I find out what type the compiler deduced when using the auto keyword?

Example 1: Simpler

auto tickTime = 0.001;

W

Answer 1

This SO answer gives a nice function for printing out the name of a type (actually a couple of implementations).

Additionally this free, open-source, header-only library gives a nice way to print out the value and type of chrono::durations.

Putting these two utilities together:

#include "chrono_io.h"
#include "type_name.h"
#include 
#include 

int
main()
{
    using namespace date;
    typedef std::ratio<1, 1> sec;
    std::chrono::duration timePerTick2{0.001};
    auto nextTickTime = std::chrono::high_resolution_clock::now() + timePerTick2;
    std::cout << type_name() << '\n';
    std::cout << std::setprecision(12) << nextTickTime.time_since_epoch() << '\n';
}

This output for me:

std::__1::chrono::time_point > >
4.8530542088e+14ns