Debuggers are key part in programming development suites. As the name suggests, they are designed to make it easier for programmers to debug the applications they write. With help of debugger you can check the code line by line and search the error.
Definition of Debug
Debugging refers to the procedure of trying to recognize and fix errors in a program.

Stop Points
A common feature of debuggers is the capacity to stop a program's execution for the short term when certain events happen.

Variable Analysis
One more common feature is the capacity to go into the program while it is temporarily stopped and check the state of variables and other data in memory to try and recognize problems.

Changes to Variables
Debuggers also let programmers to change the value of variables on the running.

Changes to Code
A few, but not all, debuggers permit the user to make changes to the program logic itself while it is still stopped, and after that start again the program with the changes executed without recompilation or restarting the program.