Objective-C Programming: The Big Nerd Ranch Guide

Local variables, frames, and the stack

Every function can have local variables. Local variables are variables declared inside a function. They exist only during the execution of that function and can only be accessed from within that function. For example, consider a function that computed how long to cook a turkey. It might look like this:

v​o​i​d​ ​s​h​o​w​C​o​o​k​T​i​m​e​F​o​r​T​u​r​k​e​y​(​i​n​t​ ​p​o​u​n​d​s​)​
{​
 ​ ​ ​i​n​t​ ​n​e​c​e​s​s​a​r​y​M​i​n​u​t​e​s​ ​=​ ​1​5​ ​+​ ​1​5​ ​*​ ​p​o​u​n​d​s​;​
 ​ ​ ​p​r​i​n​t​f​(​"​C​o​o​k​ ​f​o​r​ ​%​d​ ​m​i​n​u​t​e​s​.​\​n​"​,​ ​n​e​c​e​s​s​a​r​y​M​i​n​u​t​e​s​)​;​
}​

necessaryMinutes is a local variable. It will come into existence when showCookTimeForTurkey() starts to execute and ...