Go compilation and execution flow - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print "Hello, Go!" to the console.

Go

package main

import "fmt"

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

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

APrint

BPrintln

CPrintf

DPrintfln

Attempts:

3 left

💡 Hint

Common Mistakes

Using Print instead of Println will not add a new line.

Using Printfln is not a valid function.

The fmt.Println function prints the text followed by a new line.

2fill in blank

medium

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

Go

package main

func main() {
    var count [1] = 10
}

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

Astring

Bbool

Cint

Dfloat64

Attempts:

3 left

💡 Hint

Common Mistakes

Using string type for a number value.

Using float64 when an integer is enough.

The variable count is declared as an integer using int.

3fill in blank

hard

Fix the error in the code to correctly compile and run.

Go

package main

[1] "fmt"

func main() {
    fmt.Println("Go is fun!")
}

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

Aimport

Bpackage

Cfunc

Dvar

Attempts:

3 left

💡 Hint

Common Mistakes

Using package instead of import.

Trying to declare fmt as a variable.

The import keyword is used to include packages in Go.

4fill in blank

hard

Fill both blanks to create a map from string to int with two entries.

Go

package main

func main() {
    scores := map[string][1]{
        "Alice": [2],
        "Bob": 90,
    }
}

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

Aint

B85

Cstring

D100

Attempts:

3 left

💡 Hint

Common Mistakes

Using string as value type instead of int.

Using a string value for Alice's score.

The map keys are strings and values are integers. Alice's score is 85.

5fill in blank

hard

Fill all three blanks to define a function that returns the sum of two integers.

Go

package main

func [1](a, b [2]) [3] {
    return a + b
}

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

Aadd

Bint

Dsum

Attempts:

3 left

💡 Hint

Common Mistakes

Using different types for parameters and return.

Using a function name that does not match the action.

The function named add takes two integers and returns an integer sum.

Practice

1. What does the go build command do in Go programming?

easy

A. It compiles the code and creates an executable file.

B. It runs the code without compiling.

C. It only checks the code for errors without compiling.

D. It deletes the executable file.

Solution

1. Step 1: Understand the purpose of go build

   The go build command compiles Go source code into an executable binary file.

2. Step 2: Differentiate from other commands

   Unlike go run, go build does not run the program immediately but creates a file you can run later.

3. Final Answer:

   It compiles the code and creates an executable file. -> Option A

4. Quick Check:

   go build creates executable [OK]

Hint: Remember: build = compile and save executable [OK]

Common Mistakes:

• Confusing go build with go run
• Thinking go build runs the program immediately
• Believing go build only checks syntax

2. Which of the following is the correct way to compile and run a Go program in one step?

easy

A. go execute main.go

B. go build main.go

C. go run main.go

D. go compile main.go

Solution

1. Step 1: Identify the command that compiles and runs

   go run compiles the code and runs it immediately without creating an executable file.

2. Step 2: Check other options

   go build only compiles; go execute and go compile are not valid Go commands.

3. Final Answer:

   go run main.go -> Option C

4. Quick Check:

   go run compiles and runs [OK]

Hint: Use go run to compile and run instantly [OK]

Common Mistakes:

• Using go build to run directly
• Typing invalid commands like go execute
• Confusing compile-only and run commands

3. What will happen if you run the command go run main.go on a valid Go source file?

medium

A. It compiles the code, creates an executable file, and runs it.

B. It deletes the source file after running.

C. It only checks the code for errors but does not run it.

D. It compiles the code and runs it without creating an executable file.

Solution

1. Step 1: Understand go run behavior

   go run compiles the source code in memory and runs it immediately without saving an executable file.

2. Step 2: Eliminate incorrect options

   It compiles the code, creates an executable file, and runs it. is wrong because no executable file is saved. It only checks the code for errors but does not run it. is wrong because it runs the program. It deletes the source file after running. is incorrect as source files are never deleted.

3. Final Answer:

   It compiles the code and runs it without creating an executable file. -> Option D

4. Quick Check:

   go run compiles & runs, no file saved [OK]

Hint: Run with go run to skip saving executable [OK]

Common Mistakes:

• Assuming go run saves an executable
• Thinking go run only checks syntax
• Believing source files get deleted

4. You run go build on your Go program, but no executable file appears. What is the most likely reason?

medium

A. Go automatically deletes the executable after building.

B. The source file has syntax errors preventing compilation.

C. The executable is created but hidden in a different directory.

D. The go build command only runs the program, not build it.

Solution

1. Step 1: Understand go build behavior on errors

   If the source code has syntax errors, go build will fail and not create an executable file.

2. Step 2: Check other options

   go build does not run the program, executables are created in the current directory by default, and Go does not delete executables automatically.

3. Final Answer:

   The source file has syntax errors preventing compilation. -> Option B

4. Quick Check:

   Syntax errors block build, no executable made [OK]

Hint: Check for syntax errors if no executable appears [OK]

Common Mistakes:

• Expecting go build to run the program
• Looking in wrong directories without checking errors
• Assuming Go deletes executables automatically

5. You want to quickly test a small Go program without creating an executable file. Which command should you use and why?

hard

A. Use go run because it compiles and runs the program without saving an executable.

B. Use go build because it compiles and runs the program immediately.

C. Use go install because it runs the program without compiling.

D. Use go test because it compiles and runs the program.

Solution

1. Step 1: Identify the command for quick testing

   go run compiles and runs the program immediately without creating an executable file, perfect for quick tests.

2. Step 2: Understand why other commands don't fit

   go build creates an executable but does not run it. go install compiles and installs packages, not for quick runs. go test runs tests, not general programs.

3. Final Answer:

   Use go run because it compiles and runs the program without saving an executable. -> Option A

4. Quick Check:

   Quick test = go run [OK]

Hint: Use go run for quick compile-and-run tests [OK]

Common Mistakes:

• Using go build expecting immediate run
• Confusing go install with running code
• Trying go test for normal program execution