JavaScript: Check whether 1 appears in first or last position of a given array of integers

JavaScript Basic: Exercise-71 with Solution

Check if 1 is First/Last Element in Array

Write a JavaScript program to check whether 1 appears in the first or last position of a given array of integers. The array length must be larger than or equal to 1.

The program verifies if the number 1 is present at either the first or last position of an array of integers, ensuring the array's length is at least 1. If the condition is met, it returns true; otherwise, it returns false.

Visual Presentation:

Sample Solution:

JavaScript Code:

// Define a function named first_last_1 with a parameter nums
function first_last_1(nums)
{
  // Calculate the index of the last element in the array
  var end_pos = nums.length - 1;
  // Check if the first or last element in the array is equal to 1, and return the result
  return nums[0] == 1 || nums[end_pos] == 1;
}

// Call the function with sample arguments and log the results to the console
console.log(first_last_1([1, 3, 5]));
console.log(first_last_1([1, 3, 5, 1]));
console.log(first_last_1([2, 4, 6]));

Output:

true
true
false

Live Demo:

See the Pen JavaScript - Check whether 1 appears in first or last position of a given array of integers - basic-ex-71 by w3resource (@w3resource) on CodePen.

Flowchart:

ES6 Version:

// Define a function named first_last_1 with a parameter nums using arrow function syntax
const first_last_1 = nums => {
    // Use the logical OR operator to check if the first or last element of the array is equal to 1
    return nums[0] === 1 || nums[nums.length - 1] === 1;
};

// Call the function with sample arguments and log the results to the console
console.log(first_last_1([1, 3, 5]));
console.log(first_last_1([1, 3, 5, 1]));
console.log(first_last_1([2, 4, 6])); 

For more Practice: Solve these Related Problems:

• Write a JavaScript program that checks whether the number 1 appears as either the first or last element in an array.
• Write a JavaScript function that inspects an array and returns true if its first or last element equals 1, false otherwise.
• Write a JavaScript program that validates the array’s length before determining if 1 is positioned at the beginning or end.

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• JavaScript basic Exercises Home ↩
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