Understanding Basic Data Types in Go

In Go, we use numerical data types to represent numbers. Specifically, in this lesson, we're focusing on int and float64. The int data type represents whole integer numbers, and the float64 data type signifies decimal numbers — numbers with a decimal point.

The largest value an int can store depends on the system. It's $2^{32}$ (2147483647) on a 32-bit system and $2^{64}$ (9223372036854775807) on a 64-bit system.. Here's an example of using the int number:

var daysInWeek int = 7
fmt.Println(daysInWeek)  // This will print: 7

var maxInt64 int = 9223372036854775807
fmt.Println(maxInt64)  // This will print: 9223372036854775807

Now, let's move on to the float64 data type. We use float64 when dealing with numbers that have decimal points, also known as floating-point numbers. It provides a precision of 15–17 digits. Consider the following example:

var pi float64 = 3.1415926
fmt.Println(pi)  // This will print: 3.1415926

Let's now shift focus to the bool and byte data types.

The bool data type in Go can hold one of two possible values: true or false. This data type receives extensive use in logical expressions and decision-making. Here's a simple example:

var isEarthRound bool = true
fmt.Println(isEarthRound)  // This will print: true

var isEarthFlat bool = false
fmt.Println(isEarthFlat) // This will print: false

The byte data type is a special type of integer. Each symbol (character) is associated with some code. With byte data type we can store a symbol's code in a variable.Here's how to use it:

var firstLetterOfAlphabet byte = 'A'  // must be surrounded by SINGLE quotes
fmt.Println(firstLetterOfAlphabet) // This will print: 65 – the code for "A"

Note that in Go there is no special data type for storing characters. If you want to store a single symbol, store it inside the string data type. Let's explore it.

You'll find that the string data type is as common in Go as there are stars in the cosmos. Go treats string as a basic data type and uses it to store a sequence of characters — just a piece of text. The string is always surrounded by double quotes.

var welcome string = "Welcome to Go!"
fmt.Println(welcome) // This will print: Welcome to Go!

Interestingly, string in Go is immutable. Once a string is created, we cannot change its value.