The question is very clear. How use std::cout to debug a non-console application in Visual Studio.
The answer is very clear: you cannot. That is, Visual Studio does not support std::cout as debug tool for non-console applications.
This is a serious limitation of Visual Studio, probably a failure to meet the C++ standard even. I find it very sad to see disinformative “answers” here trying to hide this defect of their precious Visual Studio.