c++

I would like to use #include <unordered_set> in my cpp coding, but it show error when I compile. error: #error This file requires compiler and library support for the ISO C++ 2011 standard. This support is currently experimental, and must be enabled with the -std=c++11 or -std=gnu++11 compiler options. Solution Before you compile, or run do this first. cmake CMakeLists.txt Then add this in your CMakeList.txt file SET(CMAKE_CXX_FLAGS “-std=c++11 -O3”) Then try to compile again. Good Luck.