Variables

In programming, a variable is a way to store information that can be used later. Think of it like a container where you can put stuff in and take stuff out.

When we write programs in Go, we use variables to store different types of data such as numbers, text, or true/false values.

Here's an example of how we can use variables to store and use numbers in a program:

Declare a variable

package main

import "fmt"

func main() {
    // Declare variables to hold numbers
    var x int = 5
    var y int = 10

    // Add the variables together and print the result
    var sum int = x + y
    fmt.Println(sum) // Outputs: 15
}

In this code, we declare two variables x and y to hold the values 5 and 10 respectively. We then add these variables together and store the result in a new variable called sum. Finally, we print out the value of the sum variable which is 15.

Variables in Go are declared using the var keyword followed by the name of the variable and the type of data it will hold. In the example above, we declared x, y, and sum to be of type int which means they can hold whole numbers.

You can also declare variables without giving them a specific value, like this:

var z int

This creates a variable named z that has no value yet. You can assign a value to it later using the = operator:

z = 20

Or you can declare and assign a value to a variable at the same time:

var z int = 20

In Go, you can also use shorthand notation to declare and assign a value to a variable:

z := 20

This is equivalent to writing var z int = 20.

Overall, variables are an essential concept in programming and are used in many different ways. They allow us to store and manipulate data, which is what programs are all about!

Zero Values

If you don't assign a value to a variable (or a property on a struct), it will be the zero value for that type.

e.g.

var num int

println(num) // outputs: 0

Key Terms