Join Todd Perkins for an in-depth discussion in this video Controlling when tapped numbers should not appear in the calculator, part of Programming for Non-Programmers: iOS 7.
…At this point, our calculator is working as expected.…You tap a number, and it appears in the label.…However, you may have noticed, if the first number that you tap is…zero, then you see a whole bunch of zeroes appearing in the calculator.…So, I'm going to click a few zeroes.…And you'll see these pile up.…So, that's not something that we want.…Let's look at how to fix that.…I'll click the Stop button, and then what I'm…going to want to do is affect the total variable.…
Remember, total is the variable we declare…in our ViewController.h file, so back to ViewController.m.…At the bottom of tappedNumber, but still within the function, I'm…going to check to see if total is equal to 0.…And if so, I'm going to set the value…of total to whatever is inside of the value string.…So I'm going to set that equal to and then, we haven't looked at this yet, but…converting a string to an integer is even…easier than converting an integer to a string.…
In the brackets, type valueString, and then a space and then intValue.…So what that does is it takes the value inside…
If you find you'd like to learn more, see iOS App Development Essential Training, Foundations of Programming: Fundamentals, or any of the other programming courses in our library.
- Installing Xcode
- Creating an Xcode project
- Configuring the iOS Simulator
- Understanding variables
- Connecting visual objects to variables
- Understanding functions, methods, and selectors
- Connecting a button to a function
- Using conditional statements
- Setting up the user interface
- Connecting code elements to build an app
Skill Level Beginner
1. Setting Up Your Coding Environment
Creating an Xcode project1m 55s
2. Programming Building Blocks: Variables
3. Programming Building Blocks: Functions
4. Programming Building Blocks: Conditional Statements
Using conditional statements5m 21s
5. Building Your First Full Application
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