Go Functions and Methods Fundamentals Quiz Quiz

Explore essential concepts of functions and methods in Go, including syntax, receivers, return types, and usage patterns. This beginner-friendly quiz helps learners understand key Go language features for effective coding and programming.

1. Function Definition Syntax

   Which keyword is used to declare a function in Go, as shown in the example: func add(a int, b int) int?

   1. function
   2. func
   3. fn
   4. def

   Explanation: The correct keyword to declare a function in Go is 'func.' 'Function,' 'def,' and 'fn' are not valid keywords in Go; 'def' is used in another language, and 'fn' is common in yet another, but not in Go. Remember that Go uses 'func' exclusively for function and method declarations.

2. Function Return Type Placement

   In Go, where is the return type specified in a function declaration, for example: func multiply(x int, y int) int?

   1. Inside the function body
   2. Before the function name
   3. After the function parameters
   4. It is not specified

   Explanation: The return type in a Go function is always written directly after the parameters, outside the parentheses. Placing it before the function name or inside the function body is incorrect, and omitting it entirely would be invalid unless the function returns nothing. This placement keeps the declaration concise and clear.

3. Multiple Return Values

   Which of the following is the correct way to declare a function returning multiple values in Go?

   1. func stats(x int) (int, float64)
   2. function stats(x int) (int, float64)
   3. func stats(x int) int, float64
   4. def stats(x int) (int, float64)

   Explanation: Go allows multiple return values using parentheses after the parameter list, as in 'func stats(x int) (int, float64)'. Using 'function' or 'def' is incorrect in Go. Listing multiple return types without parentheses, as in the third option, is not valid syntax.

4. Method Receiver Syntax

   How do you declare a method with a receiver named 's' of type 'Shape' in Go?

   1. func (s Shape) area()
   2. func s Shape.area()
   3. method area(s Shape)
   4. func area(s Shape)

   Explanation: Go uses the syntax 'func (receiver Type) MethodName()' to declare methods, making 'func (s Shape) area()' correct. The second option uses invalid syntax and does not represent a method. The third declares a regular function, and the fourth uses a non-existent 'method' keyword.

5. Calling Methods vs Functions

   Given a method area() defined for type Rectangle, how is it called on a Rectangle variable 'r'?

   1. call area(r)
   2. Rectangle.area(r)
   3. area(r)
   4. r.area()

   Explanation: Methods in Go are called using the variable and dot notation, as in 'r.area()'. 'Rectangle.area(r)' is not correct in Go. 'area(r)' is how you call a function, not a method. 'call area(r)' is not valid syntax in Go.

6. Effect of Pointer Receivers

   What is the main difference between using a pointer receiver and a value receiver in Go methods?

   1. Pointer receivers can modify the receiver's underlying value
   2. Value receivers allow changes to the original value
   3. Pointer receivers cannot change the original value
   4. There is no difference between them

   Explanation: A pointer receiver allows a method to modify the underlying value that the receiver points to. In contrast, value receivers receive a copy, so modifications do not affect the original. The first and second options incorrectly swap these behaviors, and the fourth option is incorrect as the difference is significant.

7. Function as a Value

   In Go, how can you assign a function to a variable for later use?

   1. By declaring a variable with the function's type and assigning the function
   2. By using the 'def' keyword inside main
   3. By using '.' notation with the function name
   4. By prefixing the function name with 'u0026'

   Explanation: Go lets you assign functions to variables by matching the variable's type with the function's type, enabling flexible programming. The second option referencing 'def' is from another language. The third and fourth options do not apply to Go functions; 'u0026' gets a pointer, and '.' is for methods or fields.

8. Anonymous Functions

   What is an anonymous function in Go?

   1. A method declared inside another method
   2. A function with no receiver
   3. A function without a body
   4. A function declared without a name

   Explanation: An anonymous function is defined without a name and can be used inline or assigned to variables. Having no receiver does not make a function anonymous. A function without a body is incomplete, and Go does not support methods declared within other methods.

9. Zero Value of a Function Type

   What is the zero value of a function type variable in Go?

   1. empty string
   2. false
   3. nil
   4. 0

   Explanation: The zero value for a function type in Go is 'nil,' meaning it points to no function. 'False' is the zero value for a bool, '0' is for numbers, and '' (empty string) is for strings. If you attempt to call a nil function, it will cause a runtime panic.

10. Variadic Functions

    How do you define a function in Go that accepts an arbitrary number of integer arguments?

    1. func add(nums ...int)
    2. func add(...int nums)
    3. func add(nums varint)
    4. func add(nums []int)

    Explanation: To permit an arbitrary number of arguments, Go uses the '...int' syntax in the parameter list. Using '[]int' requires a single slice, not arbitrary arguments. '...int nums' is not valid syntax, and 'varint' is not a valid type in Go.