There is no error in my code, and I have configured Mingw in Environment Variables but showing this error. I've created this file in Dev C++ and is running well in it. The Error is :
g++.exe: error: Calculator: No such file or directory
g++.exe: error: .cpp: No such file or directory
g++.exe: fatal error: no input files
compilation terminated.
I have inserted the image for reference.

Files that I created in Visual studio code are running well and I've tried copying the code of this file in a new file and that ran. So should I do this with all the files I've created with Dev C++ or there is another method to resolve this issue?