Objective-C Programming: The Big Nerd Ranch Guide

For the more curious: conditional operators

It is not uncommon to use if and else to set the value of an instance variable. For example, you might have the following code:

i​n​t​ ​m​i​n​u​t​e​s​P​e​r​P​o​u​n​d​;​
i​f​ ​(​i​s​B​o​n​e​l​e​s​s​)​ ​{​
 ​ ​ ​ ​m​i​n​u​t​e​s​P​e​r​P​o​u​n​d​ ​=​ ​1​5​;​
}​ ​e​l​s​e​ ​{​
 ​ ​ ​ ​m​i​n​u​t​e​s​P​e​r​P​o​u​n​d​ ​=​ ​2​0​;​
}​

Whenever you have a scenario where a value is assigned to a variable based on a conditional, you have a candidate for the conditional operator, which is ?. (You will sometimes see it called the ternary operator because it takes three operands).

i​n​t​ ​m​i​n​u​t​e​s​P​e​r​P​o​u​n​d​ ​=​ ​i​s​B​o​n​e​l​e​s​s​ ​?​ ​1​5​ ​:​ ​2​0​;​

This one line is equivalent to ...