Given an array of numbers. Write a JavaScript program to find positive and negative numbers in an array.
Example:
Input: numbers_array1= [10,20, -1,22,99,20, -9]
Output: positive no’s=5, negative no’s =2Input: numbers_array2= [-121, – 78, -13, 54, -23]
Output: positive no’s=1, negative no’s=4
Example 1: This code count positive and negative numbers from the given array using JavaScript for loop. Iterate each element in the list using for loop and check if (num >= 0), the condition to check negative numbers. If the condition satisfies, then increase negative count else increase the positive count
Javascript
<script> var numbers=[10,-12,89,56,-83,8,90,-8] var pos_count=neg_count=0 for(let i=0;i<numbers.length;i++) { if (numbers[i]<0) neg_count++; else pos_count++; } console.log(`The positive numbers in an array is ${pos_count}`) console.log(`The negative numbers in an array is ${neg_count}`)</script> |
Output
The positive numbers in an array is 5 The negative numbers in an array is 3
Example 2: The following code uses JavaScript while loop.
Javascript
<script> var numbers=[7,-8,55,-87,28,74,-21,54,4] var pos_count=neg_count=i=0 while(i<numbers.length) { if (numbers[i]<0) neg_count++; else pos_count++; i++; } console.log(`The positive numbers in an array is ${pos_count}`) console.log(`The negative numbers in an array is ${neg_count}`)</script> |
Output
The positive numbers in an array is 6 The negative numbers in an array is 3
Example 3: The following code uses JavaScript using forEach Loop
Javascript
var numbers=[-8,10,23,44,-80,-15,-13,-1]var pos_count=neg_count=0numbers.forEach(element => { if (element<0) neg_count++; else pos_count++;});console.log(`The positive numbers in an array is ${pos_count}`)console.log(`The negative numbers in an array is ${neg_count}`) |
Output
The positive numbers in an array is 3 The negative numbers in an array is 5
Example 4:Using map method
Javascript
var numbers=[10,-12,89,56,-83,8,90,-8]var pos_count=neg_count=0numbers.map(function(element){ if (element<0) neg_count++; else pos_count++;});console.log(`The positive numbers in an array is ${pos_count}`)console.log(`The negative numbers in an array is ${neg_count}`) |
Output
The positive numbers in an array is 5 The negative numbers in an array is 3
Example 5:Using Recursion
Javascript
function countNumbers(numbers, index, pos_count, neg_count) { if (index < numbers.length) { if (numbers[index] < 0) { neg_count++; } else { pos_count++; } return countNumbers(numbers, index + 1, pos_count, neg_count); } else { return { pos_count, neg_count }; }}var numbers=[-8,10,23,44,-80,-15,-1]var counts = countNumbers(numbers, 0, 0, 0);console.log(`The positive numbers in an array is ${counts.pos_count}`)console.log(`The negative numbers in an array is ${counts.neg_count}`) |
Output
The positive numbers in an array is 3 The negative numbers in an array is 4
Efficient Code:-
This code is more efficient because it eliminates the need for recursion and the function calls that come with it, and instead uses a simple for loop to iterate through the array. This should result in faster execution and less memory usage.
Javascript
function countNumbers(numbers) { let pos_count = 0; let neg_count = 0; for (let i = 0; i < numbers.length; i++) { if (numbers[i] < 0) { neg_count++; } else { pos_count++; } } return { pos_count, neg_count };}var numbers = [-8, 10, 23, 44, -80, -15, -1] var counts = countNumbers(numbers);console.log(`The positive numbers in an array is $ {counts.pos_count}`)console.log(`The negative numbers in an array is $ {counts.neg_count}`) |
C++
#include <iostream>using namespace std;struct Counts { int pos_count; int neg_count;};Counts countNumbers(int numbers[], int size) { Counts counts = {0, 0}; for (int i = 0; i < size; i++) { if (numbers[i] < 0) { counts.neg_count++; } else { counts.pos_count++; } } return counts;}int main() { int numbers[] = {-8, 10, 23, 44, -80, -15, -1}; int size = sizeof(numbers) / sizeof(numbers[0]); Counts counts = countNumbers(numbers, size); cout << "The positive numbers in an array is " << counts.pos_count << endl; cout << "The negative numbers in an array is " << counts.neg_count << endl; return 0;} |
Java
class Main { static class Counts { int pos_count; int neg_count; } static Counts countNumbers(int[] numbers) { Counts counts = new Counts(); counts.pos_count = 0; counts.neg_count = 0; for (int i = 0; i < numbers.length; i++) { if (numbers[i] < 0) { counts.neg_count++; } else { counts.pos_count++; } } return counts; } public static void main(String[] args) { int[] numbers = {-8, 10, 23, 44, -80, -15, -1}; Counts counts = countNumbers(numbers); System.out.println("The positive numbers in an array is " + counts.pos_count); System.out.println("The negative numbers in an array is " + counts.neg_count); }} |
C#
using System;class MainClass { struct Counts { public int pos_count; public int neg_count; } public static Counts countNumbers(int[] numbers) { Counts counts = new Counts { pos_count = 0, neg_count = 0 }; for (int i = 0; i < numbers.Length; i++) { if (numbers[i] < 0) { counts.neg_count++; } else { counts.pos_count++; } } return counts; } public static void Main(string[] args) { int[] numbers = new int[] {-8, 10, 23, 44, -80, -15, -1}; Counts counts = countNumbers(numbers); Console.WriteLine("The positive numbers in an array is " + counts.pos_count); Console.WriteLine("The negative numbers in an array is " + counts.neg_count); }} |
Output
The positive numbers in an array is $ {counts.pos_count}
The negative numbers in an array is $ {counts.neg_count}
Example 7: using the Array.prototype.filter() method to filter out positive and negative numbers
Javascript
// defining the array of numbersvar numbers=[-8,10,23,44,-80,-15,-13,-1]// creating a new array containing only positive numbers using filter methodvar positiveNumbers = numbers.filter(function(number) { // return only numbers greater than or equal to 0 return number >= 0;});// creating a new array containing only negative numbers using filter methodvar negativeNumbers = numbers.filter(function(number) { // return only numbers less than 0 return number < 0;});// printing the count of positive numbers in the arrayconsole.log(`The positive numbers in an array is ${positiveNumbers.length}`)// printing the count of negative numbers in the arrayconsole.log(`The negative numbers in an array is ${negativeNumbers.length}`) |
Output
The positive numbers in an array is 3 The negative numbers in an array is 5
Time complexity: O(n)
Auxiliary Space: O(n)
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