Accessing Struct Fields

Use the dot operator to read and write an individual field of a struct value.

For item.Price, the selector names a field in item. With a pointer to a struct, Go also allows pointer.Price rather than requiring (*pointer).Price.

Exported fields start with an uppercase letter, which matters when using a struct from another package. Within the same package, unexported fields are accessible too.

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"

type Product struct {
	Name  string
	Price int
}

func main() {
	item := Product{Name: "Pen", Price: 10}
	fmt.Println("Before:", item.Price)
	ptr := &item
	ptr.Price = 15
	fmt.Println("Name:", item.Name)
	fmt.Println("After:", item.Price)
}

Output

Before: 10
Name: Pen
After: 15

Reading item.Price returns 10. The pointer selector ptr.Price accesses the same field through a pointer, changing it to 15. The original item reflects that update.

• Selectors on a nil pointer to a struct cannot access an actual target field.
• Field visibility across packages depends on whether the name is exported.

Add a Stock field to Product, update it through a pointer and print the product after the change.

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

You have practiced Accessing Struct Fields 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.