Hi
Maybe this question is redundant and I apologise if it is ,cause I tried searching I was not able to find the exact answer .

If I want to find out if the user-typed value is too low or too high ,how I can do it ? Like I have the user enter 78 ,but the value that he shd have typed is 80 .Then I cant just say too low .I will have to say something like "nearer to the actual value " .I have an hint thats says use Binary search .But I dont understand how it works ..
Can anybody enlighten me on this?

Thanks for your time and patience .