goLogic errorMedium

Zero-length slice copy in data transfer

Time: 0:00

BugFind the bug and fix the code

What it should do

Copy data from source slice to destination slice. Example: copyData(src) -> dst

What happens instead

copy(dst, src) copying 0 elements because len(dst) is 0

package main

import (
	"fmt"
)

func copyData(src []int) []int {
	var dst []int
	copy(dst, src)
	return dst
}

func main() {
	src := []int{1, 2, 3}
	dst := copyData(src)
	fmt.Println(dst)
}

Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).

⏱️0:00

Hints

🏆 0 hints = Flawless Solve

Think & Test Cooldown

2:00 remaining

Take a moment to read the bug symptom and trace the code with Run & Check before unlocking Hint 1.

Hint 2

Unlocks after Hint 1

Hint 3

Unlocks after Hint 2

This bug belongs to the logic errors pattern

The wrong operator, an inverted condition, a formula the right way round but backwards.

Learn the logic errors pattern Step through your own code

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goLogic errorMedium

Zero-length slice copy in data transfer

Time: 0:00

BugFind the bug and fix the code

What it should do

Copy data from source slice to destination slice. Example: copyData(src) -> dst

What happens instead

copy(dst, src) copying 0 elements because len(dst) is 0

package main

import (
	"fmt"
)

func copyData(src []int) []int {
	var dst []int
	copy(dst, src)
	return dst
}

func main() {
	src := []int{1, 2, 3}
	dst := copyData(src)
	fmt.Println(dst)
}

Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).

⏱️0:00

Hints

🏆 0 hints = Flawless Solve

Think & Test Cooldown

2:00 remaining

Take a moment to read the bug symptom and trace the code with Run & Check before unlocking Hint 1.

Hint 2

Unlocks after Hint 1

Hint 3

Unlocks after Hint 2

This bug belongs to the logic errors pattern

The wrong operator, an inverted condition, a formula the right way round but backwards.

Learn the logic errors pattern Step through your own code

Zero-length slice copy in data transfer

What it should do

What happens instead

More logic errors to practise

Zero-length slice copy in data transfer

What it should do

What happens instead

More logic errors to practise