For loop basics in Go - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of a simple for loop with continue

What is the output of this Go program?

Go

package main
import "fmt"
func main() {
    for i := 0; i < 5; i++ {
        if i == 2 {
            continue
        }
        fmt.Print(i)
    }
}

A 01234

B 0134

C 0123

D 1234

💡 Hint

Remember that continue skips the current loop iteration.

The loop prints numbers from 0 to 4 but skips printing 2 because of continue.

❓ Predict Output

intermediate

For loop with range over slice

What will this Go program print?

Go

package main
import "fmt"
func main() {
    nums := []int{10, 20, 30}
    sum := 0
    for _, v := range nums {
        sum += v
    }
    fmt.Println(sum)
}

A 60

B 0

C 10

D 30

💡 Hint

The loop adds all numbers in the slice.

The sum of 10 + 20 + 30 is 60, so the program prints 60.

🔧 Debug

advanced

Identify the error in this for loop

What error will this Go code produce when compiled?

Go

package main
func main() {
    for i := 0; i < 5; i++ {
        println(i)
    }
}

A No error, prints 0 1 2 3 4

B Runtime error: index out of range

C Syntax error: missing braces for for loop body

D Syntax error: unexpected semicolon

💡 Hint

Check the syntax rules for for loops in Go.

Go requires braces {} around the loop body; missing them causes a syntax error.

❓ Predict Output

advanced

Nested for loops output

What does this Go program print?

Go

package main
import "fmt"
func main() {
    for i := 1; i <= 2; i++ {
        for j := 1; j <= 3; j++ {
            fmt.Print(i * j)
        }
    }
}

A 123246

B 123456

C 112233

D 136236

💡 Hint

Multiply i and j for each iteration and print without spaces.

First outer loop i=1: prints 1*1=1,1*2=2,1*3=3 → 123; second i=2: 2*1=2,2*2=4,2*3=6 → 246; combined: 123246.

❓ Predict Output

expert

For loop with break and label

What is the output of this Go program?

Go

package main
import "fmt"
func main() {
Outer:
    for i := 1; i <= 3; i++ {
        for j := 1; j <= 3; j++ {
            if i*j >= 4 {
                break Outer
            }
            fmt.Print(i, j, " ")
        }
    }
}

A 11 12 21

B 1 1 1 2 2 1

C 11 12 13

D 11 12 13 21

💡 Hint

The break with label stops both loops when i*j >= 4.

Prints for (1,1):11 , (1,2):12 , (1,3):13 , (2,1):21 then at i=2 j=2 (4>=4) breaks Outer without printing more.