So I'm fairly new to JavaScript but I cannot seem to find the average in my code. I want to understand why my average is not working. Any help you guys?
function getEvenOdd() {
var oddSum = 0;
var evenSum = 0;
var num = 0;
var evenAvg = 0;
var oddAvg = 0;
while (true) {
num = parseInt(prompt("Enter a number(-1 to exit)"));
if (num == -1) {
break;
}
if (num % 2 == 0) {
evenSum += num;
} else {
oddSum += num;
}
evenAvg = evenSum / num;
oddAvg = oddSum / num;
}
alert("Sum of all even numbers is: " + evenSum);
alert("Sum of all odd numbers is: " + oddSum);
alert("Average of all even numbers is : " + evenAvg);
alert("Average of all odd numbers is: " + oddAvg);
}
On your code, to calculate the oddAvg and evenAvg, you have divided evenSum and oddSum by num variable (which is input from prompt).
And as you know, average = total sum / total count, so it's not right to divide the sum by the input number variable.
Instead of that, you need to calculate the count of odd and even numbers and divide the even and odd sum by the even and odd number counts as follows.
function getEvenOdd() {
var oddSum = 0;
var evenSum = 0;
var num = 0;
var evenAvg = 0;
var oddAvg = 0;
var evenCount = 0;
var oddCount = 0;
while (true) {
num = parseInt(prompt("Enter a number(-1 to exit)"));
if (num == -1) {
break;
}
if (num % 2 == 0) {
evenSum += num;
evenCount ++;
} else {
oddSum += num;
oddCount ++;
}
}
evenAvg = evenSum / evenCount;
oddAvg = oddSum / oddCount;
alert("Sum of all even numbers is: " + evenSum);
alert("Sum of all odd numbers is: " + oddSum);
alert("Average of all even numbers is : " + evenAvg);
alert("Average of all odd numbers is: " + oddAvg);
}
getEvenOdd();
These operations are dividing the evenSum or oddSum by the last input num.
evenAvg = evenSum / num;
oddAvg = oddSum / num;
You should divide the sum by the number of even or odd inputs.
Instead of evenSum / num use evenSum/Count of Numbers entered.
How about this solution? It is aiming to store odd and even numbers into oddList and evenList.
function getEvenOdd() {
var evenAvg = 0;
var oddAvg = 0;
var oddList = [];
var evenList = [];
var num = 0;
while (true) {
num = parseInt(prompt("Enter a number(-1 to exit)"));
if (num == -1) {
break;
}
if (num % 2 == 0) {
evenList.push(parseInt(num));
} else {
oddList.push(parseInt(num));
}
evenAvg = evenList.reduce((p, c) => p + c, 0) / evenList.length;
oddAvg = oddList.reduce((p, c) => p + c, 0) / oddList.length;
}
alert("Sum of all even numbers is: " + evenList.length);
alert("Sum of all odd numbers is: " + oddList.length);
alert("Average of all even numbers is : " + evenAvg);
alert("Average of all odd numbers is: " + oddAvg);
}
getEvenOdd();
Related
I need my code to only accept whole numbers, no decimals and should prompt an error when a decimal gets entered. I don't want a new function , I'm hoping I can just add lines to my function but I don't know what I need to add.
function number_function() {
number = parseInt(prompt('Enter a positive integer:'));
if (number < 0) {
alert('Error! Factorial for negative number does not exist. But I will show you the positive number');
number = number * -1;
let n = 1;
for (i = 1; i <= number; i++) {
n *= i;
}
alert("The factorial of " + number + " is " + n + ".");
} else if (number === 0) {
alert("Please enter a number greater than 0");
} else {
let n = 1;
for (i = 1; i <= number; i++) {
n *= i;
}
alert("The factorial of " + number + " is " + n + ".");
}
}
number_function();
You can do this to check if the number has decimals
const val = 10.7 % 1;
if (val !== 0) {
console.log('has decimals');
} else {
console.log('has no decimal');
}
JavaScript provides the built-in function Number.isInteger(n)
I'm making a program to receive a positive number and output "yes" if it's equal to its reverse;
otherwise, output "no".
What I've done so far:
HTML
<div class="column1">
<div class="input">
<button onclick="problem()"> Run the program </button>
</div>
<strong><p id="output"> </p></strong>
</div>
JS
function problem() {
var outputObj = document.getElementById("output");
var a = parseInt(prompt("Please enter a number: ", ""));
outputObj.innerHTML = "number: " + a + "<br><br>";
var reverse = 0;
while (a > 0){
num = a % 10; // the last digit
reverse = (reverse *10) + num; // calculating the reverse
a = Math.floor(a / 10); // go to next digit
}
if ( reverse == a){
outputObj.innerHTML = "yes";
}
else {
outputObj.innerHTML = "no";
}
outputObj.innerHTML = outputObj.innerHTML + "<br><br>" + "program ended";
document.getElementsByTagName("button")[0].setAttribute("disabled","true");
}
function isPalindrome(number){
return +number.toString().split("").reverse().join("") === number
}
Art for art
function palindrom(x)
{
let len = Math.floor(Math.log(x)/Math.log(10) +1);
while(len > 0) {
let last = Math.abs(x - Math.floor(x/10)*10);
let first = Math.floor(x / Math.pow(10, len -1));
if(first != last){
return false;
}
x -= Math.pow(10, len-1) * first ;
x = Math.floor(x/10);
len -= 2;
}
return true;
}
You should search for plaindromic numbers. For example the following code:
const isPalindrome = x => {
if (x < 0) return false
let reversed = 0, y = x
while (y > 0) {
const lastDigit = y % 10
reversed = (reversed * 10) + lastDigit
y = (y / 10) | 0
}
return x === reversed
}
const isPalindrome = num => {
const len = Math.floor(Math.log10(num));
let sum = 0;
for(let k = 0; k <= len; k++) {
sum += (Math.floor(num / 10 ** k) % 10) * 10 ** (len - k);
}
return sum === num;
}
console.log(isPalindrome(12321));
Need help with a JavaScript assignment from School but don't know how I should do it and was hoping for some tips?
We're supposed to create a 6 sided dice roller program and the user will have the option to choose between how many dices should be rolled, min 1 and max 5 dices.
The sum of the amount of dices used should always be displayed on the page. But if a number 6 is thrown, then this should make the program disregard it to the sum and instead throw two new dices, there should be an error message displaying this when it happens.
When all the dices are thrown the total sum of all the dices should be displayed and how many times you threw the dices.
I've managed to create this so far but I'm not sure how I should do regarding the number 6 or even if I'm on the right path here?
JS
function rollDice() {
var numDice = document.getElementById("diceNum").value;
var container = document.getElementById("dieContainer");
container.innerHTML = "";
for (var i = 0; i < numDice; i++) {
var diceRoll = Math.floor(Math.random() * 6) + 1;
container.innerHTML += '<div class="dice">' + diceRoll + '</div>';
};
var x, text;
x = document.getElementById("diceNum").value;
if (isNaN(x) || x < 1 || x > 5) {
window.alert('Input not valid');
document.getElementById("dieContainer").style.display = "none";
} else {
document.getElementById("dieContainer").style.display = "block";
}
};
EDIT
I updated it to this now
let diceThrows = numDice;
let sum = 0;
while(diceThrows > 0) {
var diceRoll = Math.floor(Math.random() * 6) + 1;
if(diceRoll == 6) {
diceThrows += 2;
console.log("You got a 6 och two new dices were thrown");
document.getElementById("msg").innerHTML = "You got a 6 och two new dices were thrown";
} else {
sum += diceRoll;
console.log(sum);
document.getElementById("msg").innerHTML = "Result: " + sum;
}
container.innerHTML += '<div class="dice">' + diceRoll + '</div>';
diceThrows -= 1;
}
I managed to display the results, but wondering now if there is a way display the results without them getting reset every time you use the function?
Replace loop for by loop while:
let diceThrows = 6;
let sum = 0;
while(diceThrows > 0) {
var diceRoll = Math.floor(Math.random() * 6) + 1;
if(diceRoll == 6) {
diceThrows += 2;
} else {
sum += diceRoll;
}
container.innerHTML += '<div class="dice">' + diceRoll + '</div>';
diceThrows -= 1;
}
You can do something like this:
function rollDice() {
var numDice = Number(document.getElementById("diceNum").value);
if (isNaN(numDice) || numDice < 1 || numDice > 5) {
window.alert('Input not valid');
return
}
var container = document.getElementById("dieContainer");
container.innerHTML = "";
var total = 0
for (var i = 0; i < numDice; i++) {
var diceRoll = Math.floor(Math.random() * 6) + 1;
container.innerHTML += '<div class="dice">' + diceRoll + '</div>';
if(diceRoll === 6) {
//Increase the maximum by 1 (because ignore 6: -1; add two: +2)
numDice++
//Decrease the current by 1 (to ignore the 6)
i--
continue
}
total += diceRoll
};
document.getElementById("diceTotal").innerText = total
document.getElementById("diceCount").innerText = numDice
}
<input type="number" id="diceNum">
<button onclick="rollDice()" >Roll Dice</button><br>
Total (without 6s): <span id="diceTotal" ></span><br>
Count of rolls (without 6s): <span id="diceCount" ></span><br>
<div id="dieContainer" ></div>
I am trying to calculate the sum of positive values smaller or equal to the entered number, for ex: 5 -> 1+2+3+4+5 = 15
I came up with this:
var num = Number(prompt("Enter a number "));
sum = 0;
i = num;
do {
sum = sum += i;
i--
document.write(sum);
} while (i > 0);
I don't understand what I am doing wrong.
i think this is correct code:
var num = Number(prompt("Enter a number "));
sum = 0;
i = num;
do
{
sum += i;
i--;
}
while (i > 0);
document.write(sum);
and i suggest you to use this formula : document.write((num * (num + 1)) / 2);
If you look closer to your task, you'll find out, that:
If Num = 1, the sequence to be summed is [1]
if Num = 2, the sequence is [1, 2]
if Num = 3, the sequence is [1, 2, 3]
You can imagine, that you have a square with sides equal to num, for example, when num = 4:
****
****
****
****
And you need to summ 1, 2, 3, 4:
***#
**##
*###
####
See? It's a square of a triangle.
It could be calculated by formula: num * (num + 1) / 2
So, you code could be:
var num = Number(prompt("Enter a number "));
document.write(num * (num + 1) / 2)
You are writing the sum on each loop instead you have to print it finally. If you want to print the numbers then keep it an array and join them with + symbol before writing. To make it in ascending order change the loop condition.
var num = Number(prompt("Enter a number "));
sum = 0;
i = 1;
nums = [];
do {
sum = sum += i;
nums.push(i++);
}
while (i <= num);
document.write(nums.join(' + ') + ' = ' + sum);
Do with increment instead of decrements.And also show result of sum outside of loop .Not with in loop.And create array to append increment value.Finally print with document.write
var num=Number(prompt("Enter a number "));
sum = 0;
i = 1;
var a=[];
do {
sum +=i;
a.push(i)
i++;
}
while (num >= i);
document.write(a.join('+')+'='+sum)
You should write the answer at the end of loop and make this simple sum += i;.
var num = Number(prompt("Enter a number"));
sum = 0;
i = num;
do {
sum += i;
i--;
}
while (i > 0);
document.write(sum);
var number = 5, // Your number
result = 0;
while ( number !== 0 ) {
result += number;
number--;
}
document.write(result);
Fast and precious solution.
Here is the case with complete check and display as you need: JAVA
public static void main ( String arg[]) {
Scanner scan = new Scanner(System.in);
int number = scan.nextInt();
System.out.println("Number entered : " + number);
int sum =1 ;
if(number > 1) {
int nextNumber = 1;
System.out.print(nextNumber);
do {
// sum of all the positive numbers
nextNumber++ ;
sum = nextNumber + sum;
System.out.print( " + " + nextNumber);
}while(nextNumber < number);
System.out.print(" = " + sum);
}
}
var num = Number(prompt("Enter a number"));
sum = 0;
for (i = num; i > 0; i--) {
sum += i;
}
document.write(sum);
I'm trying to sum all the variables,
as many times as they appear in the loop,
that is- for example if hitpoints appears
3 times(as in my code) sum -12 + -12 + -12;
And then at the end I need a final result - a
sum of all of the variable values as many
times as they appear.
function calculate(number) {
var hitpoints = -12;
var points1 = 1;
var points3 = 5;
var points5 = 10;
var pointsx = 15;
for (var i =1; i <= number; i++) {
if ( i%10 ===0) {
console.log( i + "-" + hitpoints);
} else if ((i % 3 === 0) && (i% 5 ===0)) {
console.log( i + "-" + pointsx);
} else if (i %3 ===0) {
console.log ( i + "-" + points3);
} else if (i%5 ===0) {
console.log( i + "-" + points5);
} else {
console.log( i + "-" + points1);
}
}
}
calculate(30);
I assume you want the sum of the points.
Declare a variable sum and keep incrementing
function calculate(number) {
var hitpoints = -12;
var points1 = 1;
var points3 = 5;
var points5 = 10;
var pointsx = 15;
var sum=0;
for (var i =1; i <= number; i++) {
if ( i%10 ===0) {
sum += hitpoints;
} else if ((i % 3 === 0) && (i% 5 ===0)) {
sum += pointsx;
} else if (i %3 ===0) {
sum += points3;
} else if(i%5 ===0) {
sum += points5;
} else {
sum += points1;
}
}
console.log(sum)
}
calculate(30);