Creating struct values in Go - Visual Walkthrough

Concept Flow - Creating struct values

Define struct type

↓

Create struct value

↓

Assign values to fields

↓

Use struct value in code

↓

End

This flow shows how to define a struct type, create a struct value, assign values to its fields, and then use it.

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)
}

This code defines a struct Person, creates a value with Name and Age, and prints it.

Execution Table

Step	Action	Evaluation	Result
1	Define struct type Person	Person struct with fields Name(string), Age(int)	Type Person created
2	Create struct value p with Name="Alice", Age=30	Person{Name: "Alice", Age: 30}	p holds {Name: "Alice", Age: 30}
3	Print struct value p	fmt.Println(p)	{Alice 30} printed to console
4	End of execution	-	Program ends

💡 All steps completed, struct value created and printed

Variable Tracker

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

Key Moments - 2 Insights

Why do we write field names like Name: "Alice" when creating the struct value?

Using field names (like Name: "Alice") clearly assigns values to the correct fields, as shown in execution_table step 2. This avoids confusion and errors.

Can we create a struct value without specifying field names?

Yes, but then values must be in the exact order of fields in the struct. Using field names is safer and clearer, as shown in step 2.

Visual Quiz - 3 Questions

Look at the execution table, what is the value of variable p after step 2?

A {Name: "Alice", Age: 30}

B {Age: 30, Name: "Alice"}

C undefined

D nil

💡 Hint

Check the 'Result' column in row for step 2 in execution_table

At which step is the struct value printed to the console?

A Step 1

B Step 2

C Step 3

D Step 4

💡 Hint

Look at the 'Action' column for printing in execution_table

If we omit field names when creating p, what must we do?

A Use pointers instead of values

B Provide values in the exact order of fields in the struct

C Initialize fields later one by one

D Use a map instead of a struct

💡 Hint

Refer to key_moments explanation about field names usage

Concept Snapshot

Creating struct values in Go:
- Define struct type with fields
- Create value using TypeName{Field1: val1, Field2: val2}
- Field names clarify assignments
- Values can be printed or used
- Omitting field names requires exact order

Full Transcript

This visual execution shows how to create struct values in Go. First, we define a struct type named Person with fields Name and Age. Then, we create a variable p of type Person by assigning values to Name and Age using field names. Next, we print the struct value p, which outputs {Alice 30}. The variable tracker shows p is undefined at start and holds the struct value after creation. Key moments explain why using field names is important and that omitting them requires exact order. The quiz tests understanding of variable values at steps, when printing happens, and rules about field names. This helps beginners see step-by-step how struct values are created and used.