Best practices in Go - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a package in Go.

Go

package [1]

Drag options to blanks, or click blank then click option'

Afunc

Bfmt

Cvar

Dmain

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'fmt' as a package name instead of 'main'.

Trying to declare a function or variable instead of a package.

In Go, every file starts with a package declaration. The main package is used for executable programs.

2fill in blank

medium

Complete the code to import the fmt package.

Go

import [1]fmt"

Drag options to blanks, or click blank then click option'

A"

B'

C`

D:

Attempts:

3 left

💡 Hint

Common Mistakes

Using single quotes or backticks instead of double quotes.

Using a colon instead of quotes.

In Go, import paths are enclosed in double quotes "".

3fill in blank

hard

Fix the error in the function declaration by completing the code.

Go

func [1]() {
    fmt.Println("Hello, Go!")
}

Drag options to blanks, or click blank then click option'

Afunc

BMain

Cmain

Dprint

Attempts:

3 left

💡 Hint

Common Mistakes

Capitalizing 'Main' instead of 'main'.

Using 'func' or 'print' as function names.

The entry point function in Go programs is main with a lowercase 'm'.

4fill in blank

hard

Fill both blanks to create a map of string keys to int values with a condition.

Go

ages := map[string]int{
    "Alice": 30,
    "Bob": 25,
    "Carol": 27,
}

for name, age := range ages {
    if age [1] 26 {
        fmt.Println(name, "is older than", [2])
    }
}

Drag options to blanks, or click blank then click option'

A>

Bage

C<

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' in the condition.

Printing the variable 'name' instead of 'age' for the age value.

The condition checks if age is greater than 26, and prints the name and age.

5fill in blank

hard

Fill all three blanks to create a slice of strings and print each element.

Go

names := [][1]{"Anna", "Ben", "Cara"}

for [2], [3] := range names {
    fmt.Println(index, name)
}

Drag options to blanks, or click blank then click option'

Astring

Bindex

Cname

Dint

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'int' instead of 'string' for the slice type.

Using incorrect variable names in the for loop.

The slice holds strings, and the for loop uses index and name to iterate and print each element.

Practice

1. Which of the following is a best practice when naming variables in Go?

easy

A. Use clear and descriptive names that explain the variable's purpose

B. Use single letters for all variable names to save space

C. Use names with special characters to make them unique

D. Use very long names with unnecessary details

Solution

1. Step 1: Understand variable naming importance

   Clear and descriptive names help others understand what the variable holds.

2. Step 2: Evaluate each option

   Using single letters or special characters makes code confusing. Very long names are hard to read.

3. Final Answer:

   Use clear and descriptive names that explain the variable's purpose -> Option A

4. Quick Check:

   Clear names improve readability [OK]

Hint: Pick option promoting clarity and readability [OK]

Common Mistakes:

• Choosing short, unclear variable names
• Using special characters in names
• Making names unnecessarily long

2. Which of the following Go code snippets correctly handles an error returned by a function?

easy

A. result, err := doSomething()
if err = nil {
fmt.Println("Error occurred")
}

B. result, err := doSomething()
if err == nil {
fmt.Println("Error occurred")
}

C. result, err := doSomething()
if err != nil {
fmt.Println("Error occurred")
}

D. result, _ := doSomething()
fmt.Println(result)

Solution

1. Step 1: Identify correct error check syntax

   In Go, errors are checked with 'if err != nil' to detect an error.

2. Step 2: Check each option's error handling

   result, err := doSomething() if err != nil { fmt.Println("Error occurred") } prints an error message when err is not nil, which is correct. result, err := doSomething() if err == nil { fmt.Println("Error occurred") } checks err == nil incorrectly. result, err := doSomething() if err = nil { fmt.Println("Error occurred") } uses assignment '=' instead of comparison '=='. result, _ := doSomething() fmt.Println(result) ignores the error by using _ and prints the result anyway, which is incorrect.

3. Final Answer:

   result, err := doSomething() if err != nil { fmt.Println("Error occurred") } -> Option C

4. Quick Check:

   Check error with 'err != nil' [OK]

Hint: Remember: error check is 'if err != nil' [OK]

Common Mistakes:

• Using '=' instead of '==' in conditions
• Checking 'err == nil' to detect errors
• Ignoring errors without handling

3. What will be the output of the following Go code?

package main
import "fmt"
func main() {
    nums := []int{1, 2, 3}
    sum := 0
    for _, n := range nums {
        sum += n
    }
    fmt.Println(sum)
}

medium

A. 6

B. 123

C. 0

D. Error

Solution

1. Step 1: Understand the loop and sum calculation

   The loop goes through each number in nums: 1, 2, 3 and adds them to sum.

2. Step 2: Calculate the sum

   sum = 0 + 1 + 2 + 3 = 6

3. Final Answer:

   6 -> Option A

4. Quick Check:

   Sum of [1,2,3] = 6 [OK]

Hint: Sum elements by adding each in the loop [OK]

Common Mistakes:

• Concatenating numbers as strings
• Starting sum from wrong initial value
• Misunderstanding range loop syntax

4. Identify the error in the following Go code snippet and choose the best fix:

func divide(a, b int) int {
    return a / b
}

func main() {
    result := divide(10, 0)
    fmt.Println(result)
}

medium

A. Change function to return float64 instead of int

B. Add error handling to check if b is zero before dividing

C. Remove the divide function and do division inline

D. Ignore the error since Go handles division by zero automatically

Solution

1. Step 1: Identify the problem with division by zero

   Dividing by zero causes a runtime panic in Go, which must be prevented.

2. Step 2: Choose the fix that prevents panic

   Adding error handling to check if b is zero before dividing avoids the panic. Changing return type or removing function does not fix the error. Go does not handle division by zero automatically.

3. Final Answer:

   Add error handling to check if b is zero before dividing -> Option B

4. Quick Check:

   Prevent division by zero [OK]

Hint: Always check divisor before dividing to avoid panic [OK]

Common Mistakes:

• Ignoring division by zero errors
• Assuming Go handles zero division safely
• Changing return type without fixing logic

5. You want to write a Go function that returns a map of words to their counts from a slice of strings. Which approach follows best practices for clarity, error handling, and simplicity?

hard

A. Use nested loops to count words multiple times for accuracy

B. Use global variables to store counts and update them inside the function

C. Return a pointer to the map and panic if input slice is empty

D. Use a simple loop to count words, return the map, and handle empty input gracefully

Solution

1. Step 1: Understand best practices for function design

   Functions should be simple, clear, and handle edge cases like empty input without panicking.

2. Step 2: Evaluate each option

   Use a simple loop to count words, return the map, and handle empty input gracefully uses a simple loop and handles empty input gracefully, which is best practice. Use nested loops to count words multiple times for accuracy is inefficient with nested loops. Return a pointer to the map and panic if input slice is empty uses panic and pointers unnecessarily. Use global variables to store counts and update them inside the function uses global variables, which reduces clarity and safety.

3. Final Answer:

   Use a simple loop to count words, return the map, and handle empty input gracefully -> Option D

4. Quick Check:

   Simple, clear, safe function [OK]

Hint: Keep functions simple and handle edge cases safely [OK]

Common Mistakes:

• Using complex nested loops unnecessarily
• Panicking instead of returning errors
• Using global variables inside functions