comparison of two auto variables

问题

#include <iostream>

using namespace std;

int main()
{
    auto a{1};
    auto b{1};
    if (a==b)
    {
        cout << "equal";
    }
    return 0;
}

Why does the above C++ code return an error in g++ compiler with c++11 standard, instead of printing "equal" as output?

test.cpp:9:14: error: no match for ‘operator==’ (operand types are ‘std::initializer_list’ and ‘std::initializer_list’) if (a==b) ^

回答1:

What do you think:

auto a{1};

is to compiler?

If you think it's supposed to be integer you are wrong. Compilers are lazy in determining what things are, and it's initializer_list (just as your error stated) And std::initializer_list doesn't have == operator defined (just as your compiler stated)

来源：https://stackoverflow.com/questions/38099768/comparison-of-two-auto-variables