I am a newbie in cpp programming and use visual studio code, I don't understand what is the difference between Ctrl + Alt + N(To run code) and Ctrl + F5(Run without Debugging).
Ctrl+Alt+N (Run Code) is a shortcut provided by the "Code Runner" extension you've installed. It runs the code without debugging.
Ctrl+F5 (Debug: Start without Debugging) is a VS Code default shortcut. Despite its name, it actually runs the C++ code with debugging. This is because according to the VS Code docs:
Tip: The Run action is always available, but not all debugger extensions support 'Run'. In this case, 'Run' will be the same as 'Debug'.
Apparently the C/C++ extension does not support "Run", so Ctrl + F5
will launch a debug session instead.