Why is it difficult to tell whether a program is correct? how do you go about finding bugs in your code? what kinds of bugs are revealed by testing? what kinds of bugs are not?

Why is it difficult to tell whether a program is correct?  

It's difficult to tell if a program is correct because it depends on well-documented requirements did it by the functional analyst.

How do you go about finding bugs in your code?

To find bugs, first, you have to know the scope of testing then write correctly the test plan and finally use your tester ability to realize where the bugs could be.

What kinds of bugs are revealed by testing?

What kinds of bugs are not?

If you find a bug and is not defined in the functional document, then it could be a bug or not. Then you have to ask the functional analyst for greater accuracy of the document.

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