found a bug in the implementation of the insertion sort algorithm in Chapter 23. The issue arises in the following code snippet:
function insertionSort(input) {
// Variable to store the current element being compared
let activeNumber;
// Loop through the array starting from the second element
for (let i = 1; i < input.length; i++) {
// Store the current element in the activeNumber
activeNumber = input[i];
// Inner loop to compare activeNumber with the elements before it
for (let j = i - 1; j >= 0; j--) {
if (input[j] > activeNumber) {
// Move the greater element one position ahead for the activeNumber
input[j + 1] = input[j];
} else {
// If we find an element that is smaller than or equal to the activeNumber, exit the inner loop
break;
}
}
// Place the activeNumber in its correct sorted position
input[j + 1] = activeNumber;
}
}
let myinput = [24, 10, 17, 9, 5, 9, 1, 23, 300];
insertionSort(myinput);
alert(myinput);
The bug occurs because the variable j goes out of scope, rendering the insertion sort ineffective. To address this issue, I suggest modifying the code as follows:
// ...
// Loop through the array starting from the second element
for (let i = 1; i < input.length; i++) {
// Store the current element in the activeNumber
activeNumber = input[i];
let j; // Declare j outside the loop to prevent it from going out of scope
// Inner loop to compare activeNumber with the elements before it
for (j = i - 1; j >= 0; j--) {
if (input[j] > activeNumber) {
// Move the greater element one position ahead for the activeNumber
input[j + 1] = input[j];
} else {
// If we find an element that is smaller than or equal to the activeNumber, exit the inner loop
break;
}
}
// Place the activeNumber in its correct sorted position
input[j + 1] = activeNumber;
}
// ...
This modification ensures that the variable j retains its value outside the loop, preventing any scope-related issues.
