Error: Functionality is Missing
Bug:Functionality is there,but not working properly
 
 if a software performance is not up to the mark or 
expectations of the Customer,we can say that its a failure.


Most of the times,Error and Bug are of same ,but they 
differentiate in their definition

Bug is an error in developer point of view.
Defect is an error in tester point of view.
Failure is an error in customer point of view.


Developer  -  Tester  -  Client/end user
    |            |              |
   BUG        DEFECT         FAILURE

Error is an undersirable deviation from requirement. any
problem or cause for many problems which stops the system to
perform its functionality.

Failure - any expected action that is suppose to happen.
absence of expected response for any request.


bug - any missing functionality or any actin that is
performed by the system which is not supposed to be performed
" is an error found BEFORE the appln goes into production?

Reason for the birth of bug
Wrong functionality
missing functionality
extra or unwanted functionality

BUG:Bug is an error that occurs during the execution of a 
program.

bug, (failure), error, success, pass etc are the names for 
RESULT

so....
when the analysis is done on the result then we give any of 
the namings among the groups mentions(etc)
the only exception is when we dont get the result at all is 
a FALIURE!
when we get the result then comes the remaining 
terminoloigies...Iff it is as expected the result is said 
to be pass/sucesss... etc other wise
we have the result ... but its not what has been expected 
it is an error...!  AND
the reson for an such error(S) is a BUG!

A human miskate in the coding is all "Error".
Due to this error in the coding the test engineer find the 
missmatchs is call "Defect".
When this defect is accepcted by the developer it is known 
as "Bug"
The defect is some time is also call as "Issue".



 

Regards,

Priyanka Tambad,

Software Engineer,

JAMS Technologies PVT.LTD.

Error - Human Made Mistakes in writing Code.

Bug - This Error Produces a Defect called as Bug 

Failure - Due to this bug system fails to do the expected work is called as failure.

Failure is a term used when customer is not satisfied with
the application

Error is a term used to point out programatical mistake.

If any functionality is not working as per requirments then
it is called bug/defect/Issue.