# Python Jumpstart by Building 10 Apps Transcripts Chapter: App 2: Guess that number game Lecture: Intro to the app

0:00 Hello and welcome to app number 2
0:02 this time we are going to build a game,
0:04 a guess what number I am thinking of game,
0:06 and it's going to look like this.
0:09 The program will start up
0:10 and it will randomly choose a number between 0 and 100
0:13 and then it will interact with the user
0:15 going back and forth until they figure out what that number is.
0:18 It will ask them to enter a number and it will say,
0:20 no, that's too low, no that's too high,
0:22 and then finally you can see the user was able to figure out,
0:25 hey, 71 was the number the program selected.
0:28 So, this is a pretty straight forward app,
0:31 but you are going to learn a lot while we build it.
0:33 So what specifically?
0:35 Well, we are going to focus on boolean statements
0:38 and switching between code blocks.
0:41 So we are going to start up by talking about boolean expressions,
0:45 things like x > y, y is not nothing,
0:49 the users entered some valid text those kinds of things.
0:52 And we'll use that in two basic places,
0:54 one is going to be an if, else if categories
0:57 so if the number is greater than the one you guessed
1:00 you want to print one thing
1:01 otherwise you might want to print something else
1:03 like the number is too high
1:04 no in other case print the number is too low
1:06 but also in while loops
1:07 because we want our app to go around and around
1:09 until the person, the user has selected the right number
1:13 they've guessed the right number.
1:15 We are going to use a conditional test
1:16 to keep going until the numbers match.
1:19 Closely related to this boolean concept
1:22 is something I'm calling truthiness.
1:24 You'll see that objects within Python are embued
1:26 with a truth or falseness
1:29 we'll leverage that as a key building block in our boolean expressions.
1:32 We'll also learn about type conversion
1:34 users will enter text but we need to actually work with numbers.
1:37 Previously we composed strings
1:40 by using the plus symbol
1:42 but Python has an extremely rich formatting API
1:45 and we'll start looking at it here
1:47 we are going to just get into the very basics of function
1:50 as a way to compose our app into more
1:52 understandable and maintainable building blocks
1:55 and part of that is going to be understanding code blocks
1:57 which are a little, let's say unique in Python.