JavaScript: Find the maximum number from a given positive integer by deleting exactly one digit of the given number

JavaScript Basic: Exercise-103 with Solution

Max Integer by Removing One Digit

Write a JavaScript program to find the maximum number of a given positive integer by deleting exactly one digit of the given number.

Visual Presentation:

Sample Solution:

JavaScript Code:

// Function to delete a digit from a given number and return the maximum resulting number
function digit_delete(num) {
    var result = 0, // Variable to store the maximum resulting number
        num_digits = []; // Array to store individual digits of the number

    // Extract digits of the number and store them in an array
    while (num) {
        num_digits.push(num % 10);
        num = Math.floor(num / 10);
    }

    // Iterate through each digit and generate numbers after deleting each digit
    for (var index_num = 0; index_num < num_digits.length; index_num++) {
        var n = 0; // Temporary variable to store the generated number

        // Create a new number without the current indexed digit
        for (var i = num_digits.length - 1; i >= 0; i--) {
            if (i !== index_num) {
                n = n * 10 + num_digits[i];
            }
        }

        // Store the maximum number obtained after deleting each digit
        result = Math.max(n, result);
    }

    return result; // Return the maximum resulting number
}

// Test cases
console.log(digit_delete(100)); // Example usage
console.log(digit_delete(10)); // Example usage
console.log(digit_delete(1245)); // Example usage

Output:

10
1
245

Live Demo:

See the Pen javascript-basic-exercise-103 by w3resource (@w3resource) on CodePen.

Flowchart:

ES6 Version:

// Function to delete a digit from a number and return the highest possible number after deletion
const digit_delete = (num) => {
    let result = 0; // Initialize the result variable
    let num_digits = []; // Array to store digits of the number

    // Extract digits from the number and store them in an array
    while (num) {
        num_digits.push(num % 10);
        num = Math.floor(num / 10);
    }

    // Loop through each digit to delete and find the maximum number after deletion
    for (let index_num = 0; index_num < num_digits.length; index_num++) {
        let n = 0; // Initialize a temporary variable for number formation
        for (let i = num_digits.length - 1; i >= 0; i--) {
            if (i !== index_num) {
                n = n * 10 + num_digits[i]; // Form a number excluding the indexed digit
            }
        }
        result = Math.max(n, result); // Update the result with the maximum number obtained
    }

    return result; // Return the highest possible number after deletion
}

console.log(digit_delete(100)); // Example usage
console.log(digit_delete(10)); // Example usage
console.log(digit_delete(1245)); // Example usage

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