JavaScript: Get nth largest element from an unsorted array

JavaScript Array: Exercise-34 with Solution

Write a JavaScript function to get the nth largest element from an unsorted array.

Test Data:
console.log(nthlargest([ 43, 56, 23, 89, 88, 90, 99, 652], 4));
89

Visual Presentation:

Sample Solution:

JavaScript Code:

// Function to find the nth largest element in an array
function nthlargest(arra, highest) {
    // Initialize variables for array indices, temporary storage, array length, and flags
    var x = 0,
        y = 0,
        z = 0,
        temp = 0,
        tnum = arra.length,
        flag = false,
        result = false;

    // Iterate through the array while x is less than the array length
    while (x < tnum) {
        // Increment y to the next position
        y = x + 1;

        // Check if y is less than the array length
        if (y < tnum) {
            // Iterate through the array from y to the end
            for (z = y; z < tnum; z++) {
                // Check if the element at position x is less than the element at position z
                if (arra[x] < arra[z]) {
                    // Swap the elements at positions x and z
                    temp = arra[z];
                    arra[z] = arra[x];
                    arra[x] = temp;
                    flag = true; // Set flag to true to indicate a swap
                } else {
                    continue; // Continue to the next iteration if no swap is needed
                }
            }
        }

        // Check if a swap occurred
        if (flag) {
            flag = false; // Reset the flag
        } else {
            x++; // Move to the next position if no swap occurred

            // Check if x is equal to the desired highest position
            if (x === highest) {
                result = true; // Set result flag to true if x matches the desired position
            }
        }

        // Check if the result flag is set
        if (result) {
            break; // Break out of the loop if the result is found
        }
    }

    // Return the nth largest element from the array
    return arra[highest - 1];
}

// Output the result of the nthlargest function with a sample array and position
console.log(nthlargest([43, 56, 23, 89, 88, 90, 99, 652], 4));

Output:

89

Flowchart:

ES6 Version:

// Function to find the nth largest element in an array
function nthlargest(arra, highest) {
    let x = 0,
        y = 0,
        z = 0,
        temp = 0,
        tnum = arra.length,
        flag = false,
        result = false;

    // Iterate through the array
    while (x < tnum) {
        y = x + 1;

        // Check if y is less than the array length
        if (y < tnum) {
            // Iterate through the array from y to the end
            for (z = y; z < tnum; z++) {
                // Check if the current element is greater than the element at position x
                if (arra[x] < arra[z]) {
                    // Swap the elements
                    temp = arra[z];
                    arra[z] = arra[x];
                    arra[x] = temp;
                    flag = true;
                } else {
                    continue;
                }
            }
        }

        // Check if a swap occurred
        if (flag) {
            flag = false;
        } else {
            // Move to the next position
            x++;

            // Check if x is equal to the desired highest position
            if (x === highest) {
                result = true;
            }
        }

        // Check if the result is found
        if (result) {
            break;
        }
    }

    return arra[highest - 1];
}

// Output the result of the nthlargest function with a sample array and position
console.log(nthlargest([43, 56, 23, 89, 88, 90, 99, 652], 4));

Live Demo:

See the Pen JavaScript - Get nth largest element from an unsorted array - array-ex- 34 by w3resource (@w3resource) on CodePen.

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