What is the need for debugger tool?

Question :

What is the need for debugger tool?

Debugger tools are very useful especially if the code is big or the error is not very clear, it becomes very difficult to manually figure out the origin and cause of the problem. Debugger tools here prove very handy and useful. They show us the line by line execution and its result on variables interactively and help a programmer get to the root of the problem.