Answer 1

If I suspect a variable's value is the culprit I used to print out the value here and there and track down where it's change/calculation didn't come as expected, pretty lame, but it works for small code, large code I guess may need help from debugging tool, probably : )

Answer 2

@Flamice, I'm afraid I can't give you much details, but basically it's a tool that knows what the debugged program do, what value it wrote to memory, which system function it called, something like that, detailed things that developers need to know what were wrong so they know what to fix : )

Hth, cmiiw

Answer 3

A debugger is for example able to execute your code line by line which is quite useful. It also could show the values of all variables at each step.