Go Function Parameters and Arguments
Go Function Parameters and Arguments – Complete Guide with Examples
In Go (Golang), functions can accept inputs that allow them to work with different values. These inputs are called parameters and arguments.
Understanding parameters and arguments is essential for writing reusable, flexible, and clean Go functions.
What Are Parameters and Arguments?
Parameters → Variables defined in the function declaration
Arguments → Actual values passed to the function when it is called
Example
- Parameters receive values
- Arguments supply values
Basic Function Parameters in Go
Syntax
Example
Function Call
Multiple Parameters
Go allows multiple parameters in a function.
- Parameters are comma-separated
- Each parameter has a type
Short Parameter Type Syntax
When multiple parameters share the same type, you can shorten the syntax.
- Cleaner code
- Common Go style
Passing Arguments to Functions
Arguments must match:
Order
Number
Type
- Wrong order or type causes a compile-time error.
Call by Value in Go (Important)
Go passes arguments by value by default.
- Original value remains unchanged
Call by Reference Using Pointers
To modify the original value, use pointers.
- Pass memory address
- Original value changes
Passing Arrays, Slices, and Maps
Arrays (Copied)
- Arrays are copied
Slices (Reference-like)
- Changes reflect outside
Maps (Reference-like)
- Original map is modified
Variadic Parameters (...)
Variadic functions accept any number of arguments.
Usage
- Flexible
- Common in Go standard library
Default Parameters (Not Supported)
Go does not support default parameters.
Invalid
Alternative
Named Arguments (Not Supported)
Go does not support named arguments.
Invalid
- Go prefers simplicity and clarity
Parameter vs Argument – Quick Comparison
| Feature | Parameter | Argument |
|---|---|---|
| Defined in | Function | Function call |
| Acts as | Variable | Value |
| Lifetime | Inside function | At call time |
| Type | Required | Must match |
Common Mistakes
- Passing wrong data type
- Expecting call by reference by default
- Modifying parameters without pointers
- Confusing parameters with arguments
- Overusing pointers unnecessarily
Best Practices
- Keep parameter lists short
- Use meaningful parameter names
- Prefer value passing unless needed
- Use pointers for large data
- Avoid unnecessary complexity
Interview Questions: Go Parameters & Arguments
1. What is the difference between parameters and arguments?
Parameters are variables, arguments are values.
2. Does Go support call by reference?
Indirectly, using pointers.
3. Can Go functions have default parameters?
No.
4. What are variadic parameters?
Parameters that accept multiple values.
5. How are slices passed in Go?
By reference-like behavior.
Summary
- Parameters define input
- Arguments pass values
- Go uses call by value
- Pointers enable modification
- Variadic functions add flexibility
Mastering function parameters and arguments in Go helps you write modular, reusable, and efficient programs
