Hi, replit tries to compile both of the files into the same cpp file, so you have to configure the run button:
https://docs.replit.com/programming-ide/configuring-run-button#configuring-the-run-button

Here is the code you could add in your .replit file:

run = "g++ main.cpp ; ./a.out"

And then to run the other file:

run = "g++ 'how to accept user input.cpp' ; ./a.out"

[Simple Solution]: Change the main to something else, it worked for me. There are two main() change one of their names to main2() or something...