Basic Go Programs

Learn basic go programs through an executable example, then connect the small demonstration to production code.

Practice short complete programs before combining larger features. A typical beginner exercise declares variables, computes a result, and displays it with fmt.

Values in these introductory examples are defined in code so readers can run them in an online compiler without interactive input.

Follow this diagram before executing the example. Check where a value or decision changes what runs next.

This example is a complete program. Save it as main.go or paste it into the Go Playground.

Go code

package main

import "fmt"

func main() {
	first, second := 12, 8
	fmt.Println("First:", first)
	fmt.Println("Second:", second)
	fmt.Println("Sum:", first+second)
	fmt.Println("Difference:", first-second)
}

Output

First: 12
Second: 8
Sum: 20
Difference: 4

The first two lines display assigned variables. Addition and subtraction produce 20 and 4, respectively.

• Use := only when declaring a new variable in a function.
• Do not assume an uninitialized variable is undefined: Go supplies a zero value.

Add multiplication and a carefully chosen integer-division example.

Tip: Edit the example above, predict the output, and run the modified code to test your reasoning.

You have practiced Basic Go Programs in a small, self-contained program. The important habit is to predict what runs, inspect the actual output and distinguish the language rule from the particular example.

Before continuing, make sure you can explain the program to someone who has not seen it, including the line that changes its result.