I am trying to display an array of test scores and above them, the average of those scores. Here is the code I am using:
var clickDisplayResults = function () {
$("results").value = "";
function calculate(scores) {
var i = 0, sum = 0, len = scores.length;
while (i < len) {
sum = sum + scores[i++];
};
return sum / len;
};
var average = calculate(scores);
$("results").value = "The average score is: " + parseInt(average) + "\n";
$("results").value += "High Score: " + Math.max.apply(null, scores) + "\n";
$("results").value += "Low Score: " + Math.min.apply(null, scores) + "\n" + "\n";
for (var i = 0; i < names.length; i++) {
$("results").value += names[i] + ", " + scores[i] + "\n";
};
When I do this, however, I get an average in a ridiculous range after adding a new score.
Here is the add score code:
var clickAddScore = function () {
if ( $("name").value == "" || $("score").value < 0 || $("score").value > 100 || isNaN($("score").value) ) {
alert("Please enter a valid name and score");
$("name").value = "";
$("score").value = "";
return false;
};
else {
names[names.length] = $("name").value;
scores[scores.length] = $("score").value;
$("name").value = "";
$("score").value = "";
};
};
Any advice would be appreciated.
You are working with a string and treating it like a number
console.log("100" + 100);
You need to convert the string to a number. You can use parseInt, parseFloat, Number, or Unary plus.
Your code is a bit inefficient since you keep accessing the DOM for the value so declare some variables. And your else statement was wrong.
var clickAddScore = function() {
var studentName = $("name").value.trim();
var score = Number($("score").value);
if (studentName == "" || score < 0 || score > 100 || isNaN(score)) {
alert("Please enter a valid name and score");
} else {
names.push(studentName);
scores.push(score);
}
$("name").value = "";
$("score").value = "";
}
Related
I need to assign instances of my object as values in my array, but when I try to add let to my loop for collecting user input, I get an error stating that "[" is an unexpected token. This is a new technique to me so I'm not sure if this is even a practical method for making a table. Any help is appreciated.
<script>
function generateTable() {
var tblStart = "<table>";
//This is the header line for my table.
var tblMeat = "<tr> <td><b>Name</b></td> <td><b>Attendance</b></td> <td><b>Homework</b></td> <td><b>Midterm</b></td> <td><b>Final</b></td> <td><b>Course Grade</b></td> <td><b>Round Grade</b></td> <td><b>Letter Grade</b></td> </tr>";
var tblStop = "</table>";
//This determines the number of rows.
var rowCount = prompt("How many students are in the class?");
//I want to assign instances of Student to this array which will be used to fill the table cells.
var pupil = [NUMBER(rowCount)];
//This object should process user entries and use them to calculate the total grade, rounded grade, and letter grade.
function Student(name, attendance, homework, mGrade, fGrade) {
this.name = name;
this.attend = attendance;
this.homewrk = homework;
this.midter = mGrade;
this.fingrad = fGrade;
this.course = function () {
var attGrade = this.attend * 0.1;
var hwkGrade = this.homewrk * 0.2;
var midGrade = this.midter * 0.3;
var finGrade = this.fingrad * 0.4;
var combGrade = attGrade + hwkGrade + midGrade + finGrade;
return combGrade.toFixed(2);
};
this.round = Math.round(this.course);
this.letter = function() {
if(this.course < 60) {
return '<p style="color:red;">F</p>';
} else if(this.course >= 60 && this.course <= 69.9){
return "D";
} else if(this.course >= 70 && this.course <= 79.9) {
return "C";
} else if(this.course >= 80 && this.course <= 89.9) {
return "B";
} else if(this.course >= 90 && this.course <= 100) {
return "A";
};
};
}
/*This loop should collect user input based on the declared number of students, and assign input values to instances of
Student based on which execution of the loop is being run. I am getting an error stating "[" is unexpected for line 79.
*/
for (var r = 0; r < rowCount; r++) {
var studentN = prompt("Enter student name.");
var studentA = prompt("Enter student attendance.");
var studentH = prompt("Enter student homework grade.");
var studentM = prompt("Enter student midterm grade.");
var studentF = prompt("Enter student final grade.");
let pupil[r] = new Student(studentN, studentA, studentH, studentM, studentF);
}
for(var i = 0; i < rowCount; i++) {
tblMeat += "<tr>";
for(var j = 0; j < 8; j++) {
tblMeat += "<td>" + pupil[i].name + "</td><td>" + pupil[i].attend + "</td><td>" + pupil[i].homewrk + "</td><td>" + pupil[i].midter + "</td><td>" + pupil[i].fingrad + "</td><td>" + pupil[i].course() + "</td><td>" + pupil[i].round + "</td><td>" + pupil[i].letter() + "</td>";
}
tblMeat += "</tr>";
}
//This just puts it all together.
var completeTable = tblStart + tblMeat + tblStop;
document.getElementById("placetable").innerHTML = completeTable;
}
</script>
I ran your program through uglifyJS. It's actually for compressing javascript code, but when there is a lot of code to debug, it's a life changer.
The script told me:
Parse error: Unexpected token: punc ([)
Line 59, column 16
let pupil[r] = new Student(studentN, studentA, studentH, studentM, studentF);
You're trying to define an already existing variable. Remove "let".
A tiny advice for the future.
function displayEvent(array) {
var vOutput = "";
var ind = 0;
for(var i = 0; i < array.length; i++) {
ind += 1;
vOutput += "Name " + ind + ": " + array[i].name + ", Age " + array[i].age + "<br />";
}
document.getElementById("output").innerHTML = vOutput;
}
function init() {
var arrEvent = [];
var objEvent = {};
objEvent.name = prompt("Enter name of Event");
objEvent.age = prompt("Enter number of Guests");
arrEvent.push(objEvent);
while(objEvent.name.length > 0) {
objEvent.name = prompt("Enter name of Event");
objEvent.age = prompt("Enter number of Guests");
if(objEvent.name.length > 0) {
arrEvent.push(objEvent);
}
}
displayEvent(arrEvent);
}
window.onload = init;
Trying to print an object array into the HTML paragraph id and whenever I execute the code above I get the correct output but the array elements just show as blank.
You are always pushing the same object into your array.
Change to:
function displayEvent(array) {
var vOutput = "";
var ind = 0;
for(var i = 0; i < array.length; i++) {
ind += 1;
vOutput += "Name " + ind + ": " + array[i].name + ", Age " + array[i].age + "<br />";
}
document.getElementById("output").innerHTML = vOutput;
}
function init() {
var arrEvent = [];
var name = '';
var age = '';
name = prompt("Enter name of Event");
age = prompt("Enter number of Guests");
arrEvent.push({name: name, age: age});
while(name.length > 0) {
name = prompt("Enter name of Event");
age = prompt("Enter number of Guests");
if(name.length > 0) {
arrEvent.push({name: name, age: age});
}
}
displayEvent(arrEvent);
}
window.onload = init;
This is the code I currently have. I am having issues displaying the ordinals as I am not sure what for loop to put then in. Can someone please assist?
var bandsString = "";
var newBandString = "";
var bandsListArray = ["Linkin Park", "Atmosphere", "Rage Against The Machine", "Immortal Technique", "System of a Down"];
for (var i = 0; i < bandsListArray.length; i++) {
var currentBand = bandsListArray[i];
bandsString += "<li> My #" + [i + 1] + " band is " + currentBand + "</li>";
}
var bands = i;
if (bands == 0) {
bands = i + "st";;
} else if (bands == 1) {
bands = i + "nd";
} else if (bands == 2) {
bands = i + "rd";
} else if (bands == 3) {
bands = i + "th";
} else if (bands == 4) {
bands = i + "th";
} else {
}
for (var i = 0; i < bandsListArray.length; i++) {
var newBandList = bandsListArray[i];
newBandString += "<li>My # " + [i + 1] + " band is " + currentBand + "</li>";
}
document.write(bandsString);
document.write(newBandString);
I'm not exactly sure what you're trying to do, but does this help? Instead of manually working out how to put the correct ordinal suffix ('st', 'nd', 'rd', etc.) on the numbers, I googled a function.
The ordinal_suffix_of function works like this:
This first part is the start of the function. Hopefully this is self-explanatory. We're creating a function that accepts one parameter, that will be named i inside the function.
function ordinal_suffix_of(i) {
This next part defines j and k. You can declare multiple variables while only typing var once by using commas, as this code does:
var j = i % 10,
k = i % 100;
This would do exactly the same thing:
var j = i % 10;
var k = i % 100;
The percent sign (%) is called "modulus" and is a mathematical operator. What it does is divide the left operand by the right operand and returns the remainder. So in the case of j, it's being assigned remainder of dividing i by 10. If i was 14, for example, j would be 4. If i was 179, j would be 9. The same thing happens for k except that it's divided by 100 instead of 10.
What it's effectively doing is extracting the last 1 digit (for j) and the last 2 digits (for k) and then just checking (in the if statements) what ordinal suffixes they should have.
The reason for k is that you always want numbers ending in 1, 2, or 3 to have the suffixes st, nd , and rd except when the number ends in 11, 12, or 13, in which case it should get the suffix th. So for example, 112 should be 112th, and 313513 should be 313513th. k handles this by making it so that if the number ends in 11, 12, or 13 we only add th. Note that 11 % 100 will result in 11, so this works for 11, 12, and 13 as well.
var bandsString = "";
var newBandString = "";
var bandsListArray = ["Linkin Park", "Atmosphere", "Rage Against The Machine", "Immortal Technique", "System of a Down"];
for (var i = 0; i < bandsListArray.length; i++) {
var currentBand = bandsListArray[i];
bandsString += "<li> My #" + (i + 1) + " band is " + currentBand + "</li>";
}
for (var i = 0; i < bandsListArray.length; i++) {
var newBandList = bandsListArray[i];
newBandString += "<li>My " + ordinal_suffix_of(i + 1) + " band is " + newBandList + "</li>";
}
function ordinal_suffix_of(i) {
var j = i % 10,
k = i % 100;
if (j == 1 && k != 11) {
return i + "st";
}
if (j == 2 && k != 12) {
return i + "nd";
}
if (j == 3 && k != 13) {
return i + "rd";
}
return i + "th";
}
document.write(bandsString);
document.write(newBandString);
Try this, just make the code more simple
var bandsString = "";
var newBandString = "";
var bandsListArray = ["Linkin Park", "Atmosphere", "Rage Against The Machine", "Immortal Technique", "System of a Down"];
for (var i = 0; i < bandsListArray.length; i++) {
var currentBand = bandsListArray[i];
bandsString += "<li> My #" + [i + 1] + " band is " + currentBand + "</li>";
newBandString += "<li> My #" + numeric(i+1) + " band is " + currentBand + "</li>";
}
function numeric(i){
var bands = i+"th";
if (i == 1) {
bands = i + "st";;
} else if (i == 2) {
bands = i + "nd";
} else if (i == 3) {
bands = i + "rd";
}
return bands;
}
document.write(bandsString);
document.write(newBandString);
If this is what you are trying to achieve is:
My 2nd band is Atmosphere
Then this how you might achieve it
var bandsString = "";
var newBandString = "";
var bandsListArray = ["Linkin Park", "Atmosphere", "Rage Against The Machine", "Immortal Technique", "System of a Down"];
for (var i = 0; i < bandsListArray.length; i++) {
var currentBand = bandsListArray[i];
bandsString += "<li> My #" + (i + 1) + " band is " + currentBand + "</li>";
newBandString += "<li>My " + numberSuffix(i + 1) + " band is " + currentBand + "</li>";
}
function numberSuffix(number){
if(number % 10==1) return number+'st';
if(number % 10==2) return number+'nd';
if(number % 10==3) return number+'rd';
return number+'th';
}
document.write(bandsString);
document.write(newBandString);
So, i'm adding 2 characters 4 levels together (hp, attack, strength and defense) and then comparing them. However I am having a problem. when the numbers are added together they're added together as a string so it outputs as follows. 9060951/99709940 instead of 246 (90+60+95+1)/308 (99+70+99+40). Here is what I am doing.
function calculate(player1, player2) {
var total1 = player1.getTotal();
var total2 = player2.getTotal();
var differencePercentage;
if(total1 > total2) {
differencePercentage = total2 + "/" + total1 + " = " + (total2/total1);
} else {
differencePercentage = total1 + "/" + total2 + " = " + (total1/total2);
}
var percentage = differencePercentage;
return percentage;
}
function Player(hp, attack, strength, defense) {
this.hp = parseInt(hp);
this.attack = parseInt(attack);
this.strength = parseInt(strength);
this.defense = parseInt(defense);
this.getTotal = function() {
var total = 0;
total = hp + attack + strength + defense;
return total;
}
}
Why is this happening?
You are parsing the Ints into this.hp, this.attack etc. in your Player function but not into the getTotal function
Try this
this.getTotal = function() {
var total = 0;
total = this.hp + this.attack + this.strength + this.defense;
return total;
}
I can't figure this out I keep getting stuck in a loop. I don't know if I have my calculation or if statements in the right areas, please I could use some help. My output is like a end of day report. I could really use the help.
<script type="text/javascript">
<!--
// assignments
var cost, nachosCounter, moneyCollected, nachosRate, corndogRate, hotdogRate;
var hamAccum, hotdogAccum, corndogAccum, nachosAccum, hamburgerRate;
var beginDay, orderType, hamCounter, hotdogCounter, corndogCounter;
var totalHotdog, totalNachos, totalCorndog, totalHamburger, moneyCollected;
var hamburgerRate = 4;
var hotDogRate = 2;
var cornDogRate = 3;
var nachosRate = 5;
var hamCounter = 0;
var hotdogCounter = 0;
var corndogCounter = 0;
var nachosCounter = 0;
var beginDay = "yes"
//initalizing loop
beginDay = "yes"
//start loop
while (beginDay == "yes")
{
orderType = prompt("hamburger, hotdog, corndog, nachos", "");
if (orderType == "hamburger")
{
hamCounter = hamCounter + 1;
if (hamCounter == 1)
{
hamAccum = "<br>The total number of hamburgers purchased: " + hamCounter;
}
else
{
hamAccum = hamAccum + "<br>" + hamCounter;
}
}
else if (orderType == "hotdog")
{
hotdogCounter = hotdogCounter + 1;
if (hotdogCounter == 1)
{
hotdogAccum = "The total number of hotdog purchased:<br>" + hotdogCounter;
}
else
{
hotdogAccum = hotdogAccum + "<br>" + hotdogCounter;
}
}
if (orderType == "corndog")
{
corndogCounter = corndogCounter + 1;
if (corndogCounter == 1)
{
corndogAccum = "<br>The total number of corndogs purchased: <br>" + corndogCounter;
}
else
{
corndogAccum = corndogAccum + "<br>" + corndogCounter;
}
}
if (orderType == "nachos")
{
nachosCounter = nachosCounter + 1;
if (nachosCounter == 1)
{
nachosAccum = "<br>The total number of nachos purchased: <br>" + nachosCounter;
}
else
{
nachosAccum = nachosAccum + "<br>" + nachosCounter;
}
}
totalHotdog = hotdogCounter*hotDogRate;
totalHamburger = hamCounter*hamburgerRate;
totalCorndog = corndogCounter*cornDogRate;
totalNachos = nachosCounter*nachosRate;
moneyCollected = totalNachos+totalCorndog+totalHamburger+totalHotdog;
beginDay = prompt("More to add?", "yes");
}
//output
document.write(hotdogAccum);
document.write(hamAccum);
document.write(corndogAccum);
document.write(nachosAccum);
document.write("<br>The total dollar amount for hotdog: $ " + totalHotdog);
document.write("<br>The total dollar amount for hamburger: $ " + totalHamburger);
document.write("<br>The total dollar amount for corndogs: $" + totalCorndog);
document.write("<br>The total dollar amount for nachos: $" + totalNachos);
document.write("The total amount of money collected: $" + moneyCollected);
// -->
</script>