Bug and defect are most times used interchangeably, but that does not mean they are the same. A bug is a result you get that is quite different from the real or expected result. Most program developers are familiar with the term bug because it has a lot to do with the quality of their products. At times, a program might contain bugs, and they won’t affect its normal functioning. However, in some cases, the presence of bugs can affect the functions of a program. If a program contains a lot of bugs, it can cause the program to shut down. A defect, on the other hand, describes the inclusion of some features that were not added to a program in the first place. A perfect example is when you try to use a program, and you start noticing some features that should not be part of a program. A defect can occur as a result of poor quality control, and some other factors.
Testing is known to be one of the things that you should do to ensure that you will be able to know the different defects that are available. When you say defect, this refers to the variance between the result that you have expected and what the actual result is. When you make a mistake when you are coding, you call this an error. If you would not see this error immediately and the defect is also not detected, that is what you would call a “bug.” There are instances when you know that there are various requirements that you need to do but since you cannot reach those requirements, then you can accept the failure or fix the bugs and defects to improve what you are developing.