Accessing struct fields in Go - Step-by-Step Execution

Concept Flow - Accessing struct fields

Define struct type

↓

Create struct variable

↓

Access field using dot

↓

Use or print field value

↓

END

First, we define a struct type, then create a variable of that type. We access fields using the dot (.) operator and use the values.

Execution Sample

Go

package main

import "fmt"

type Person struct {
    Name string
    Age  int
}

func main() {
    p := Person{Name: "Alice", Age: 30}
    fmt.Println(p.Name)
}

This code defines a Person struct, creates a variable p, and prints the Name field.

Execution Table

Step	Action	Variable/Field	Value	Output
1	Define struct type Person	Person	struct with fields Name(string), Age(int)
2	Create variable p	p	Person{Name: "Alice", Age: 30}
3	Access field p.Name	p.Name	"Alice"
4	Print p.Name			Alice
5	End of program

💡 Program ends after printing the Name field value.

Variable Tracker

Variable	Start	After Step 2	After Step 3	Final
p	undefined	Person{Name: "Alice", Age: 30}	Person{Name: "Alice", Age: 30}	Person{Name: "Alice", Age: 30}
p.Name	undefined	"Alice"	"Alice"	"Alice"
p.Age	undefined	30	30	30

Key Moments - 2 Insights

Why do we use a dot (.) to access struct fields?

The dot operator connects the struct variable to its fields. For example, p.Name accesses the Name field inside p. See execution_table step 3.

Can we access a field before creating the struct variable?

No, the struct variable must exist first. In the table, p is created at step 2 before accessing p.Name at step 3.

Visual Quiz - 3 Questions

Look at the execution table, what is the value of p.Name at step 3?

A "30"

B undefined

C "Alice"

D Person struct

💡 Hint

Check the 'Value' column at step 3 in the execution_table.

At which step is the struct variable p created?

A Step 1

B Step 2

C Step 3

D Step 4

💡 Hint

Look at the 'Action' column in execution_table for variable creation.

If we change p.Name to "Bob", what will be printed at step 4?

A "Bob"

B "Alice"

C 30

D Error

💡 Hint

Refer to variable_tracker to see how changing p.Name affects output.

Concept Snapshot

Accessing struct fields in Go:
- Use dot (.) to get or set fields: variable.field
- Struct variable must be created before access
- Example: p.Name accesses Name field of p
- Fields hold values like strings or ints
- Use fmt.Println to display field values

Full Transcript

This visual trace shows how to access fields of a struct in Go. First, we define a struct type Person with fields Name and Age. Then we create a variable p of type Person with Name set to "Alice" and Age to 30. We access the Name field using p.Name and print it. The dot operator connects the variable to its fields. The variable tracker shows how p and its fields hold values during execution. The program ends after printing "Alice".