Variables and constants

Variables are spaces in computer's memory to store values that can be modified during the execution of the program. Variables and constants have a type like the ones described in preceding text. Although, you don't need to explicitly write the type of them (although you can do it). This property to avoid explicit type declaration is what is called Inferred types. For example:

    //Explicitly declaring a "string" variable 
    var explicit string = "Hello, I'm a explicitly declared variable" 

Here we are declaring a variable (with the keyword var) called explicit of string type. At the same time, we are defining the value to Hello World!.

    //Implicitly declaring a "string". Type inferred 
inferred := ", I'm an inferred variable " 

But here we are doing exactly the same thing. We have avoided the var keyword and the string type declaration. Internally, Go's compiler will infer (guess) the type of the variable to a string type. This way you have to write much less code for each variable definition.

The following lines use the reflect package to gather information about a variable. We are using it to print the type of (the TypeOf variable in the code) of both variables:

    fmt.Println("Variable 'explicit' is of type:", 
        reflect.TypeOf(explicit)) 
    fmt.Println("Variable 'inferred' is of type:", 
        reflect.TypeOf(inferred)) 

When we run the program, the result is the following:

$ go run main.go
Hello, I'm a explicitly declared variable
Hello, I'm an inferred variable
Variable 'explicit' is of type: string
Variable 'inferred' is of type: string

As we expected, the compiler has inferred the type of the implicit variable to string too. Both have written the expected output to the console.