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

## 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: **

**JavaScript Code:**

```
// Function to count even numbers before the given number in the array
function find_numbers(arr_num, num) {
var result = 0; // Counter variable to store the count of even numbers
for (var i = 0; i < arr_num.length; i++) {
if (arr_num[i] % 2 === 0 && arr_num[i] !== num) { // Check if number is even and not equal to 'num'
result++; // Increment the counter for each even number
}
if (arr_num[i] === num) { // Check if the current number matches 'num'
return result; // Return the count of even numbers encountered so far
}
}
return -1; // Return -1 if 'num' is not found in the array
}
// Example usage of the function
console.log(find_numbers([1, 2, 3, 4, 5, 6, 7, 8], 5));
console.log(find_numbers([1, 3, 5, 6, 7, 8], 6));
```

Output:

2 0

**Live Demo: **

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

**Flowchart: **

**ES6 Version:**

```
// Function to find numbers in an array that are even and not equal to a specific number
const find_numbers = (arr_num, num) => {
let result = 0; // Initialize the count of even numbers not equal to 'num'
for (let i = 0; i < arr_num.length; i++) {
if (arr_num[i] % 2 === 0 && arr_num[i] !== num) {
result++; // Increment count for even numbers not equal to 'num'
}
if (arr_num[i] === num) {
return result; // Return the count when 'num' is found in the array
}
}
return -1; // Return -1 if 'num' is not found in the array
};
// Example usage of the function
console.log(find_numbers([1, 2, 3, 4, 5, 6, 7, 8], 5)); // Output: 2 (even numbers not equal to 5: 2, 4)
console.log(find_numbers([1, 3, 5, 6, 7, 8], 6)); // Output: -1 (6 not found in the array)
```

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