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2. Logic and Loops
Overview
In this chapter, we'll use branching logic and loops to demonstrate how logic can be controlled and selectively run. With these tools, you'll have control of what you do and don't want to run based on the values of variables.
By the end of this chapter, you will be able to implement branching logic using if, else, and else if; use switch statements to simplify complex branching logic; create looping logic using a for loop; loop over complex data collections using range; and use continue and break to take control of the flow of loops.
Introduction
In the previous chapter, we looked at variables and values and how we can temporarily store data in a variable and make changes to that data. We're now going to look at how we can use that data to run logic, or not, selectively. This logic allows you to control how data flows through your software. You can react to and perform different operations based on the values in your variables.
The logic could be for validating your user's inputs. If we were writing code to manage a bank account, and the user asked to withdraw some money, we could check that they asked for a valid amount of money. We would check that they had enough money in their account. If the validation was successful, we would use logic to update their balance, transfer the money, and show a success message. If the validation failed, we'd show a message explaining what went wrong.
If your software is a virtual world, then logic is the physical law of that world. Like the physical laws...
Summary
In this chapter, we discussed logic and loops. These are the foundational building blocks to build complex software. They allow you to have data flow through your code. They let you deal with collections of data by letting you execute the same logic on every element of the data.
Being able to define the rules and laws of your code are the starting points of codifying the real world in software. If you are creating banking software and the bank has rules about what you can and can't do with money, then you can also define those rules in your code.
Logic and loops are the essential tools that you'll use to build all your software.
In the next chapter, we'll look at Go's type system and the core types it has available.
