Go Struct
Go Struct – Complete Tutorial
In Go (Golang), a struct is a user-defined data type that allows you to group related data together.
It is similar to classes in OOP, but Go structs do not support inheritance.
What is a Struct in Go?
A struct:
Groups multiple variables (fields) of different data types
Represents real-world entities
Is the foundation of Go data modeling
Think of struct as a blueprint for data, not behavior.
Why Use-Structs?
- Organize related data
- Create custom data types
- Improve code readability
- Used in APIs, JSON, databases
- Essential for Go backend development
Basic-Struct Definition
Syntax
Example
Creating & Using a Struct
Method-1: Declare then assign
Method 2: Structs Literal (Most Common)
Method 3: Without Field Names
Order must match struct definition.
Access Structs Fields
Structs with Functions (Methods)
Method on Struct
Usage:
This is how Go achieves OOP-like behavior.
Pointer to Structs (Very Important)
Passing struct by value copies data.
Use pointer to modify original struct.
- Memory efficient
- Interview favorite
Anonymous Structs
Useful for quick, temporary data
Nested Structs
Access:
Structs vs Map (Interview)
| Feature | Structs | Map |
|---|---|---|
| Type safety | Yes | No |
| Fixed fields | Yes | No |
| Performance | Faster | Slower |
| JSON usage | Excellent | Yes |
Use structs for fixed models, maps for dynamic data.
Structs with JSON (Real-World Use)
Used in REST APIs
Common Mistakes
- Forgetting to export fields (capital letters)
- Passing structs instead of pointer
- Using structs when map is better (or vice versa)
- Field order mistake in literals
Interview Questions & MCQs
Q1. What is a structs in Go?
A) Function
B) Package
C) User-defined data type
D) Interface
Answer: C
Q2. How do you access structs fields?
A) s->name
B) s[name]
C) s.name
D) s::name
Answer: C
Q3. Why use pointer to structs?
A) Faster compilation
B) Modify original data
C) Avoid syntax
D) Create copy
Answer: B
Q4. Can structs have methods?
A) Yes
B) No
Answer: A
Q5. Structs fields must be capitalized to?
A) Compile
B) Export outside package
C) Use pointer
D) Save memory
Answer: B
Real-Life Use Cases
- API request/response models
- Database records
- Configuration objects
- Backend services
- Microservices
Summary
Structs = custom data type in Go
Groups related fields
Supports methods (OOP-style)
Use pointers for performance
Widely used in APIs & backend
Must-know topic for Go interviews
