Basic data types in Go - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a variable of type int with value 10.

Go

var number [1] = 10

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

Aint

Bstring

Cfloat64

Dbool

Attempts:

3 left

💡 Hint

Common Mistakes

Using string instead of int for a number.

Using float64 when an integer is needed.

The keyword int declares an integer variable in Go.

2fill in blank

medium

Complete the code to declare a variable of type bool with value true.

Go

var isActive [1] = true

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

Aint

Bfloat64

Cstring

Dbool

Attempts:

3 left

💡 Hint

Common Mistakes

Using int or string instead of bool for true/false values.

The type bool is used for true or false values in Go.

3fill in blank

hard

Fix the error in the code by choosing the correct type for the variable.

Go

var price [1] = 19.99

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

Abool

Bstring

Cfloat64

Dint

Attempts:

3 left

💡 Hint

Common Mistakes

Using int for decimal numbers causes errors.

Using bool or string for numeric values.

The value 19.99 is a decimal number, so the variable must be float64.

4fill in blank

hard

Fill both blanks to create a map from string keys to int values.

Go

var scores map[[1]][2]

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

Astring

Bint

Cfloat64

Dbool

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping key and value types.

Using float64 or bool for keys or values incorrectly.

Maps in Go use map[keyType]valueType. Here, keys are strings and values are integers.

5fill in blank

hard

Fill all three blanks to declare and initialize a slice of strings with three names.

Go

var names = [][1]{"[2]", "[3]", "Alice"}

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

Astring

BBob

CJohn

Dint

Attempts:

3 left

💡 Hint

Common Mistakes

Using int instead of string for the slice type.

Mixing up the order of names.

The slice holds strings, so the type is string. The names are "John", "Bob", and "Alice".

Practice

1. Which Go data type is used to store true or false values?

easy

A. float64

B. int

C. string

D. bool

Solution

1. Step 1: Understand the data types

   In Go, bool is used for true/false values, int for whole numbers, string for text, and float64 for decimals.

2. Step 2: Match the type to true/false

   Since true/false are boolean values, the correct type is bool.

3. Final Answer:

   bool -> Option D

4. Quick Check:

   Boolean type = bool [OK]

Hint: True/false values always use bool type in Go [OK]

Common Mistakes:

• Choosing int for true/false
• Using string for boolean values
• Confusing float64 with bool

2. Which of the following is the correct way to declare an integer variable named age in Go?

easy

A. int age

B. var age int

C. age := int

D. var int age

Solution

1. Step 1: Recall Go variable declaration syntax

   In Go, variables are declared with var followed by the name and then the type.

2. Step 2: Check each option

   var age int matches this syntax: var age int. Others do not follow Go syntax.

3. Final Answer:

   var age int -> Option B

4. Quick Check:

   Variable declaration = var name type [OK]

Hint: Use 'var name type' to declare variables in Go [OK]

Common Mistakes:

• Writing type before variable name
• Using := without initialization
• Mixing order of var and type

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

package main
import "fmt"
var x int = 10
var y float64 = 5.5
var z string = "Go"
func main() {
	fmt.Println(x, y, z)
}

medium

A. 10 5.5 Go

B. 10 5 Go

C. 10 5.5 "Go"

D. Error: cannot print variables

Solution

1. Step 1: Understand variable values

   Variable x is 10 (int), y is 5.5 (float64), and z is "Go" (string).

2. Step 2: Check fmt.Println output

   fmt.Println prints values separated by spaces without quotes for strings.

3. Final Answer:

   10 5.5 Go -> Option A

4. Quick Check:

   Print values as is, strings without quotes [OK]

Hint: fmt.Println prints strings without quotes by default [OK]

Common Mistakes:

• Expecting quotes around strings
• Confusing float64 with int
• Thinking fmt.Println causes error

4. Find the error in this Go code snippet:

var name string = 123
fmt.Println(name)

medium

A. fmt.Println requires parentheses

B. Missing semicolon after declaration

C. Cannot assign int to string variable

D. Variable name is a reserved keyword

Solution

1. Step 1: Check variable assignment types

   The variable name is declared as string but assigned the integer 123, which is a type mismatch.

2. Step 2: Verify other syntax

   Semicolons are optional in Go, fmt.Println is correctly used, and name is not a reserved keyword.

3. Final Answer:

   Cannot assign int to string variable -> Option C

4. Quick Check:

   Type mismatch error = assigning int to string [OK]

Hint: Match variable type and assigned value type exactly [OK]

Common Mistakes:

• Assigning wrong type value
• Thinking semicolon is mandatory
• Confusing reserved keywords

5. You want to store a person's age, height in meters, name, and if they are a student. Which Go variable declarations are correct?

hard

A. var age int
var height float64
var name string
var isStudent bool

B. var age float64
var height int
var name bool
var isStudent string

C. var age string
var height string
var name int
var isStudent int

D. var age bool
var height bool
var name float64
var isStudent int

Solution

1. Step 1: Match data types to real-world data

   Age is a whole number, so int. Height can have decimals, so float64. Name is text, so string. Student status is true/false, so bool.

2. Step 2: Check each option

   var age int var height float64 var name string var isStudent bool matches these types correctly. Others assign wrong types to variables.

3. Final Answer:

   var age int var height float64 var name string var isStudent bool -> Option A

4. Quick Check:

   Correct types for data = int, float64, string, bool [OK]

Hint: Use int for whole numbers, float64 for decimals, string for text, bool for true/false [OK]

Common Mistakes:

• Mixing int and float64
• Using bool for text
• Assigning string to boolean