What is Go - Practice Questions & Exercises

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Go program?

Look at this Go code. What will it print when run?

Go

package main
import "fmt"
func main() {
    fmt.Println("Hello, Go!")
}

A Hello, Go!

B hello, go!

C Hello Go!

D Compilation error

💡 Hint

Check the exact string inside the quotes and capitalization.

The program prints exactly what is inside the quotes with correct capitalization.

🧠 Conceptual

intermediate

What is Go mainly used for?

Choose the best description of what Go is mainly used for.

A A markup language for web pages

B A tool for designing websites with drag and drop

C A database management system

D A language for building fast and reliable server software

💡 Hint

Think about what kind of programs Go is famous for.

Go is designed for building fast, reliable server and network programs.

❓ Predict Output

advanced

What does this Go code print?

What is the output of this Go program?

Go

package main
import "fmt"
func main() {
    var x int = 5
    var y int = 10
    fmt.Println(x + y)
}

A Compilation error

B 15

C 5 + 10

D 510

💡 Hint

Look at the variables and the operator used.

The program adds two integers and prints the sum.

❓ Predict Output

advanced

What error does this Go code cause?

What error will this Go code produce when compiled?

Go

package main
func main() {
    var a int = "hello"
}

A missing return statement

B undefined: a

C cannot use "hello" (type string) as type int in assignment

D no error

💡 Hint

Check the type of the variable and the value assigned.

You cannot assign a string to an int variable in Go.

🧠 Conceptual

expert

Which feature is unique to Go compared to many other languages?

Choose the feature that Go has which is not common in many other programming languages.

A Built-in support for concurrent programming with goroutines

B Automatic memory management with garbage collection

C Object-oriented programming with classes and inheritance

D Dynamic typing for variables

💡 Hint

Think about how Go handles multiple tasks at the same time.

Go has goroutines, lightweight threads, built into the language for easy concurrency.

Practice

1. What is Go primarily used for?

easy

A. Designing websites with HTML

B. Building fast and reliable software

C. Creating video games only

D. Writing scripts for Photoshop

Solution

1. Step 1: Understand Go's purpose

   Go is designed to build software that runs quickly and reliably.

2. Step 2: Compare options

   Options A, C, and D describe other technologies or limited uses, not Go's main purpose.

3. Final Answer:

   Building fast and reliable software -> Option B

4. Quick Check:

   Go = fast, reliable software [OK]

Hint: Go is known for speed and reliability [OK]

Common Mistakes:

• Confusing Go with web design languages
• Thinking Go is only for games
• Assuming Go is a scripting tool

2. Which of the following is the correct way to start a Go program?

easy

A. package main

func main() {
// code
}

B. start program {
// code
}

C. begin main() {
// code
}

D. function main() {
// code
}

Solution

1. Step 1: Recognize Go program structure

   Go programs start with a package declaration and a main function.

2. Step 2: Check syntax correctness

   package main func main() { // code } uses correct Go syntax: 'package main' and 'func main()'. Others use invalid keywords or syntax.

3. Final Answer:

   package main\n\nfunc main() {\n // code\n} -> Option A

4. Quick Check:

   Go starts with package main and func main() [OK]

Hint: Go programs start with 'package main' and 'func main()' [OK]

Common Mistakes:

• Using 'start' or 'begin' instead of 'package' and 'func'
• Omitting the package declaration
• Using wrong function syntax

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

package main
import "fmt"
func main() {
    fmt.Println("Hello, Go!")
}

medium

A. Hello Go

B. fmt.Println("Hello, Go!")

C. Hello, Go!

D. Error: missing main function

Solution

1. Step 1: Understand fmt.Println usage

   fmt.Println prints the string with a newline to the console.

2. Step 2: Check the program structure

   The program has a valid main function and imports fmt correctly, so it runs and prints the string.

3. Final Answer:

   Hello, Go! -> Option C

4. Quick Check:

   fmt.Println prints text with newline [OK]

Hint: fmt.Println prints exactly what is inside quotes [OK]

Common Mistakes:

• Expecting output without quotes
• Confusing print with return
• Thinking program lacks main function

4. Identify the error in this Go code:

package main
import "fmt"
func main() {
    fmt.Println("Welcome to Go")
    fmt.Println(Welcome to Go)
}

medium

A. Missing quotes around string in second fmt.Println

B. Missing import statement

C. No main function defined

D. Incorrect package name

Solution

1. Step 1: Check string usage in fmt.Println

   The second fmt.Println lacks quotes around the string, causing a syntax error.

2. Step 2: Verify other parts

   Import and main function are correct, package name is valid.

3. Final Answer:

   Missing quotes around string in second fmt.Println -> Option A

4. Quick Check:

   Strings need quotes in fmt.Println [OK]

Hint: Strings must be in quotes inside fmt.Println [OK]

Common Mistakes:

• Forgetting quotes around strings
• Assuming import is missing
• Thinking main function is absent

5. You want to write a Go program that prints "Go is fun!" only if a variable fun is true. Which code snippet correctly does this?

hard

A. package main
import "fmt"
func main() {
fun := true
fmt.Println("Go is fun!")
}

B. package main
import "fmt"
func main() {
fun := true
if fun == false {
fmt.Println("Go is fun!")
}
}

C. package main
import "fmt"
func main() {
fun := false
if fun {
fmt.Println("Go is fun!")
}
}

D. package main
import "fmt"
func main() {
fun := true
if fun {
fmt.Println("Go is fun!")
}
}

Solution

1. Step 1: Understand the condition to print

   The program should print only if 'fun' is true, so the if condition must check 'fun' directly.

2. Step 2: Analyze each option

   package main import "fmt" func main() { fun := true if fun { fmt.Println("Go is fun!") } } checks 'if fun' when fun is true, so it prints. package main import "fmt" func main() { fun := true if fun == false { fmt.Println("Go is fun!") } } prints if fun is false, wrong. package main import "fmt" func main() { fun := false if fun { fmt.Println("Go is fun!") } } fun is false, so no print. package main import "fmt" func main() { fun := true fmt.Println("Go is fun!") } prints unconditionally, ignoring fun.

3. Final Answer:

   package main\nimport \"fmt\"\nfunc main() {\n fun := true\n if fun {\n fmt.Println(\"Go is fun!\")\n }\n} -> Option D

4. Quick Check:

   Print only if fun is true [OK]

Hint: Use 'if fun' to check true boolean variable [OK]

Common Mistakes:

• Checking if fun == false instead of fun
• Setting fun to false by mistake
• Printing without condition