Which is better between black box testing and white box testing?

Black box testing - first lets understand the term - u can not see inside a black box. so u just know that what goes in and what comes out. for eg. at airport you checkin your bag and at next airport u get your bag. what happens in between you dont know.

So in blackbox testing we do functional testing. Some techniques are boundary value analysis, class, etc. You do not need to know how the code works and you don't see it. You just need to know what it should do and then check does it do it by entering in data and seeing what happens. As a very simple example, it may be a program to do calculations. You enter some numbers and check if the program gives you the correct results. You don't need to know exactly how it does the calculation, just that it works. You don't need to know anything about programming to do black box testing.

White box: or glass box testing - You know what is everything inside and processed. This requires knowledge of the code of the program and knowledge of the language being used. You can check what each line does and how it does it. So for our calculations, you would see how those calculations are actually done. You can then fix any problems you find. People who don't know anything about programming cannot do white box testing.

Sometimes if an error is found in black box testing, it is necessary to look directly at the code to see what is going wrong, and you are then performing white box testing.