JavaScript: Find the number of even values in sequence before the first occurrence of a given number

Last update on May 30 2022 09:56:27 (UTC/GMT +8 hours)

JavaScript Basic: Exercise-110 with Solution

Write a JavaScript program to find the number of even values in sequence before the first occurrence of a given number.

Sample sequence = [1,2,3,4,5,6,7,8]
Given number: 5
Output: 2

Sample Solution:

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title> Find the number of even values in sequence before the first occurrence of a given number</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function find_numbers(arr_num, num) {
    var result = 0;
    for (var i = 0; i < arr_num.length; i++)
    {
        if (arr_num[i] % 2 === 0 && arr_num[i] !== num) {
            result++;
        }
        if (arr_num[i] === num) 
        {
            return result;
        }
    }
    return -1;
}

console.log(find_numbers([1,2,3,4,5,6,7,8], 5))
console.log(find_numbers([1,3,5,6,7,8], 6))

Sample Output:

2
0

Flowchart:

ES6 Version:

function find_numbers(arr_num, num) {
    let result = 0;
    for (let i = 0; i < arr_num.length; i++)
    {
        if (arr_num[i] % 2 === 0 && arr_num[i] !== num) {
            result++;
        }
        if (arr_num[i] === num) 
        {
            return result;
        }
    }
    return -1;
}

console.log(find_numbers([1,2,3,4,5,6,7,8], 5))
console.log(find_numbers([1,3,5,6,7,8], 6))

Live Demo:

See the Pen javascript-basic-exercise-110 by w3resource (@w3resource) on CodePen.

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Next: Write a JavaScript program to check a number from three given numbers where two numbers are equal, find the third one.

JavaScript: Tips of the Day

How to insert an item into an array at a specific index (JavaScript)?

What you want is the splice function on the native array object.

arr.splice(index, 0, item); will insert item into arr at the specified index (deleting 0 items first, that is, it's just an insert). In this example we will create an array and add an element to it into index 2:

var arr = []; arr[0] = "Jani"; arr[1] = "Hege"; arr[2] = "Stale"; arr[3] = "Kai Jim"; arr[4] = "Borge"; console.log(arr.join()); arr.splice(2, 0, "Lene"); console.log(arr.join());

Ref: https://bit.ly/2BXbp04