cppLogic errorMedium

Unexpected behavior in integer-based list traversal

Time: 0:00

BugFind the bug and fix the code

What it should do

Reverse the order of elements in a given list. Example: reverseList([1,2,3]) -> [3,2,1]

What happens instead

The program runs but produces an incorrect result or causes an infinite loop.

#include <vector>

std::vector<int> reverseList(std::vector<int> list) {
    int start = 0;
    int end = list.size() - 1;
    while (start <= end) {
        std::swap(list[start], list[end]);
        start++;
        end--;
    }
    return list;
}

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 logic errors pattern

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

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#include <vector> std::vector<int> reverseList(std::vector<int> list) { int start = 0; int end = list.size() - 1; while (start <= end) { std::swap(list[start], list[end]); start++; end--; } return list; }

Unexpected behavior in integer-based list traversal

What it should do

What happens instead

More logic errors to practise

Unexpected behavior in integer-based list traversal

What it should do

What happens instead

More logic errors to practise