[MUSIC] As you saw Huang struggle through a really bad example of the technical phone screen. And then, you saw and improved example of how Huang used some of these skills that we've been talking about to avoid the pitfalls she had in her first interview example. Now, let's take another look at how she does, how she would actually do in this technical phone screen situation because as we mentioned in the beginning of this lesson, Huang is actually a rockstar, she's very technically solid, she knows how to solve this problem. She doesn't necessarily do it exactly perfectly the first time but if she were in this technical phone screen situation, she would have a very solid technical background and get the answer to this problem right pretty much on the first try. And many of you will be in a situation like that in your technical phone screens. You may not struggle that much solving the problem, you may have to think about it, but you'll get the answer right. So let's take a look at what a very good example of a technical phone screen interview would look like by looking at how Huang does it. >> Could you please write a method that converts a string to a number? >> So I'm going to go through an example first to make sure that I understand this question correctly. So I'll be giving a string, so let's say, I get a string, 123. So can this string be like a negative number, or- >> It could be, but let's just start with positive integers. >> Okay, so I don't have to worry about floating point or number e or pi. >> Not right now, then I'll ask you to extend it afterwards. >> Awesome, and that I should get back 123 as the output. All right. So what I think I will do is I will convert this string to a char array, so that I can separate the digits. And I will add them back up to integer. So strToNum and String input. So is it okay if I use the library function that converts the string to char array? >> Yes. >> So charArray, so I believe there's a levering method just converts a string to charArray. >> It's actually a method on the string objects itself. >> Okay, so it's just input.toCharArray, and is it possible for the input to be empty or not numerical should I consider that? >> You should definitely consider that case. >> All right, so in this case if my array's or my string's empty, I would throw an exception to tell the user that they've entered an illegal argument. So put not string and so then they can enter different. Or is it okay to just like return zero? >> What do you think? Do you think I should throw in exception or throw in zero? Which one's better? >> Well, if we return zero in this case we might not know if what happens if the user actually enters zero. We could return a negative number but then we have to worry about it later, what to do when this method does return a negative number. So I think throwing out exceptions is the best case here. >> Sure. >> Okay, so I'm going to throw a new illegalArgumentException [BLANK AUDIO] and I'm going to say Must be a valid number string and then I can check later if my digits are indeed numerical. >> All right, so you said this, so I know you know. But I think you need to throw that exception when input is empty, not when it's not empty. >> Yes, so this should be equals, and actually I shouldn't be using equals at all, because it's a string, and string is an object. So in this case, I should be using equals to actually check the equality. And I want to make sure that the input is not null, because I assume that it could be null as well. So if input is null, or that its empty, that would throw an IllegalArgumentException. And I think I'm ready to loop through the charArray. So this is just the for loop construct. And getting the length of the charArray and length is just a field inside the array. And then, inside this for loop I'm going to loop through each digits and then added to an integer value [BLANK AUDIO] and this is what I will be returning later so I can just do some simple math by multiplying ten to increase the number of places and I'll add in the digits. Is it okay if I use the character method to convert the character to digit? >> Sure. >> Okay, so, Character.toDigit(charArr[I] and then I'll return value here, and then let me just walk through going back to my example to see this actually works [MUSIC] >> Great, so you did a good job catching the problem with the empty string. Do you see any other problems that could arise here? >> Yeah, so the characters could be not numerical. So if I catch a case where it's not numerical that I should just return it away. So I can either do the check inside the current folder or I can have a separate folder to just not do at all. So- >> You don't have to write that there, that's fine. >> Okay. Cool. >> And my other question is to make things even simpler, can you think of a way to do it without using that library call? Just relying on the askey values themselves? >> Okay. Askey values. So I know these are askey characters and they all have their unique askey value. They're all consecutive from zero to nine. So I guess the differences between the values are the same as their numeric values, if that makes sense, so if I have digit nine, the difference between digit nine to digit zero would be nine. Yeah, so I think I can use that. >> Can you read the line of code to replace your lab result? >> All right, so I think it's really simple. I just need to subtract each digit from the character 0. And then that should give me the right value. >> All right, great, thanks. >> Awesome thank you. >> All right, so now you've seen three examples of how one might answer this question in a technical phone screen during a phone screening. One was very bad, it was a train wreck. You definitely want to avoid that. The second sort of set of videos that you saw was improvements, taking somebody who's got some good ideas, a really good way of starting the problem and their fairly solid, and improving on that first example which was terrible to really do a better job on the interview. And then, the last example you saw was someone whose really a rockstar. They're really very solid. They know exactly how to solve this problem and the interview goes very, very smoothly. So what we're going to ask you to do next is to go back to that example that you filmed at the very beginning of this week. Where you were the one who was solving a technical coding question in a Google Doc. We ask you to film it. We haven't asked you to touch it. We told you that you won't have to show it to anyone else, but you are going to have to go back and watch it yourself. So we're going to have some assessment criteria for you. We want you to go back and self assess. Figure out what you did well, and where there's room for improvement. And ultimately in your final assignment for this week, you'll be re-doing that activity to see how much you can improve based on what we've talked about. Coming up in the next lesson we'll talk about some confidence building strategies, and in particular, a couple things that can really affect confidence. And so, knowing about these things and then meeting them head on will help you not only apply the strategies that we talked about in this lesson but go into these technical phone screens with much more confidence. So I hope you'll have fun. It'll be a little uncomfortable. It's always uncomfortable to watch yourself on video. But I hope you have fun and that you'll learn a lot from this self-assessment.
