Go program structure - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of a simple Go program

What is the output of this Go program?

Go

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

A Compilation error

B hello, go!

C Hello Go!

D Hello, Go!

💡 Hint

Look at the exact string inside fmt.Println and remember Go is case-sensitive.

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

❓ Predict Output

intermediate

Variable declaration and output

What will this Go program print?

Go

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

A Compilation error

B 5

C 0

D x

💡 Hint

The variable x is assigned 5 before printing.

The program prints the value of x, which is 5.

❓ Predict Output

advanced

Understanding package and import

What error does this Go program produce?

Go

package main
func main() {
    fmt.Println("Hi")
}

A undefined: fmt

B no error, prints Hi

C syntax error: missing import

D runtime error

💡 Hint

Check if the fmt package is imported before using it.

The program uses fmt.Println but does not import fmt, causing undefined error.

❓ Predict Output

advanced

Multiple functions and main execution

What is the output of this Go program?

Go

package main
import "fmt"
func greet() {
    fmt.Println("Hello")
}
func main() {
    greet()
    fmt.Println("World")
}

A

Hello
World

B

World
Hello

C Hello World

D Compilation error

💡 Hint

Functions run in the order they are called inside main.

The greet function prints Hello, then main prints World on a new line.

🧠 Conceptual

expert

Go program entry point and package rules

Which statement about Go program structure is correct?

A The main() function can be in any package, not necessarily main.

B Go programs can run without a main() function if package main is present.

C Every Go executable program must have package main and a main() function.

D Packages are optional in Go programs.

💡 Hint

Think about what Go requires to start running a program.

Go requires package main and main() as the entry point for executables.