rustNull / UndefinedMedium

Segmentation fault during linked list traversal

Time: 0:00

BugFind the bug and fix the code

What it should do

Traverse a singly linked list and collect all values. Example: traverse_list(head) -> Vec<i32>

What happens instead

thread 'main' panicked at 'called `Option::unwrap()` on a `None` value', src/libcore/option.rs:341:21

struct Node { value: i32, next: Option<Box<Node>> }

fn traverse_list(head: Option<Box<Node>>) -> Vec<i32> {
    let mut values = Vec::new();
    let mut current = head;
    while let Some(node) = current {
        values.push(node.value);
        current = node.next;
    }
    values
}

fn main() {
    let node1 = Box::new(Node { value: 1, next: None });
    let node2 = Box::new(Node { value: 2, next: Some(node1) });
    let head = Some(node2);
    println!("{:?}", traverse_list(head));
}

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

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This bug belongs to the null and undefined errors pattern

Cannot read properties of undefined, NoneType has no attribute, NaN appearing from nowhere.

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struct Node { value: i32, next: Option<Box<Node>> } fn traverse_list(head: Option<Box<Node>>) -> Vec<i32> { let mut values = Vec::new(); let mut current = head; while let Some(node) = current { values.push(node.value); current = node.next; } values } fn main() { let node1 = Box::new(Node { value: 1, next: None }); let node2 = Box::new(Node { value: 2, next: Some(node1) }); let head = Some(node2); println!("{:?}", traverse_list(head)); }

Segmentation fault during linked list traversal

What it should do

What happens instead

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Segmentation fault during linked list traversal

What it should do

What happens instead

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