Debugger Another important tool is Debugger. Every programmer should be familiar with it. Debugger is used to debug the program i.e. to correct the logical errors. Using debugger we can control our program while it is running. We can stop the execution of our program at some point and can check the values in different variables, can change these values etc. In this way we can trace the logical errors in our program and can see whether our program is producing the correct results. This tool is very powerful, so it is complex too.