I'm a student creating a 3-guess game with JavaScript. My game doesn't work properly, I believe Math.random is generating a new number at every stage of the game. I would be most grateful if somebody helps me define a single number for the variable randomNumber.
Here's the JavaScript:
function game()
{
var randomNumber = Math.floor(Math.random()*11);
var userGuess = prompt ("Guess what number I'm thinking of? (It's between 0 & 10)");
if (userGuess === randomNumber)
{
alert ("Good Guess, you must be psychic!");
}
else
{
var userGuess2 = prompt ("Dohhh! You got it wrong. You have 2 more chances.");
}
if (userGuess2 === randomNumber)
{
alert ("Good Guess, you must be psychic!");
}
else
{
var userGuess3 = prompt ("Dohhh! You got it wrong. You have 1 more chance.");
}
if (userGuess3 === randomNumber)
{
alert ("Good Guess, you must be psychic!");
}
else
{
alert ("Bad luck. The number was: " + randomNumber);
}
}
prompt returns a string. You are using the strict equality operator, ===, to compare strings with numbers. They will never be equal.
Use the abstract equality operator, ==, or convert the strings to numbers before comparing with the strict equality operator.
Also, your function should probably return after a correct guess, rather than prompting for more guesses.
Here's a suggestion for a cleaned-up version of your code:
function playGame(guesses)
{
// By default, give the player 3 guesses.
guesses = guesses || 3;
var randomNumber = Math.floor(Math.random()*11);
var userGuess = prompt("Guess what number I'm thinking of? (It's between 0 & 10)");
// Repeat the following logic whenever the user guesses incorrectly.
while (userGuess !== randomNumber.toString())
{
--guesses;
if (guesses === 0)
{
alert("Bad luck. The number was: " + randomNumber);
return false;
}
userGuess = prompt("Dohhh! You got it wrong. You have " + guesses + " more chance(s).");
}
alert("Good Guess, you must be psychic!");
return true;
}
Notice that it's now more flexible (you can give the user a configurable number of guesses) while also reducing code duplication: instead of repeating the same block of logic (with small differences), there is really just one bit of logic that can be repeated as many times as you like.
Related
I created a small number guessing game in JAVASCRIPT but the program only runs correctly if I get the answer right on the first attempt, if I get it right on any other attempt then it just stops prompting me and the page loads infinitely till it reaches an error, even though I do not see any infinite loop situation in my code. Basically, It should stop loading once I guessed the number right , but again, it only does this if I get it correctly on the first try (btw I am using VS code Live Server so I am suspecting something might be off with it). Would really appreciate if someone can find any faults:
let maximum = parseInt(prompt("Enter a maximum number"));
const targetNum = Math.floor((Math.random() * maximum) + 1);
while (!maximum) {
maximum = parseInt(prompt("Enter a valid number"))
}
console.log(targetNum);
let guess = parseInt(prompt("Enter your first guess"));
let attempts = 1;
while (guess !== targetNum) {
console.log(new Date());
attempts++;
if (guess > targetNum) {
guess = prompt("TOO HIGH! Try again")
} else if (guess < targetNum) {
guess = prompt("TOO LOW! Try again")
}
}
console.log(`You got it! it took you ${attempts} attempts`);
You could also simplify your code by changing while (guess !== targetNum) { ... } to while (guess != targetNum) { ... }, as this comparison would do the type conversion implicitly for you. (Write less - do more ;-)).
Kindly Check. This code keeps giving me "you lose" even tho my "guess" is equal to targetNum.
let maximum = prompt("Tell us your maximum number");
const targetNum = Math.floor(Math.random() * maximum) + 1
console.log(targetNum)
let guess = prompt("Enter your first guess!");
if (guess === targetNum) {
console.log("you win")
} else {
console.log("you lose")
}
guess === targetNum
You are using the strict equality operator, which is a good practice. It compares types and values. It does not do conversions.
Your problem is that prompt() returns a string and and you are comparing it to a number. Try casting it to a number like this const guess = Number(prompt('Enter your first guess!')).
You can read more about type casting here:
https://medium.com/swlh/typecasting-and-coercion-in-javascript-f0d59b0a86db
https://dev.to/antonmelnyk/understanding-javascript-type-conversions-43n
You can read more about the prompt() here:
https://developer.mozilla.org/en-US/docs/Web/API/Window/prompt
That is because prompt() returns a string, not a number, while targetNum returns a number. A strict comparison of these two will always return false.
The solution is to ensure you convert guess into a number prior to comparison. You can use the unary plus + to do so:
let maximum = prompt("Tell us your maximum number");
const targetNum = Math.floor(Math.random() * maximum) + 1
let guess = +prompt("Enter your first guess!");
if (guess === targetNum) {
console.log("you win")
} else {
console.log("you lose")
}
"==" compares two data irrespective of datatype and "===" compares two data along with datatype.
your first variable datatype is number and second variable datatype is string.
use "==" operator instead of "==="
Simple error
if (guess === targetNum) {
the syntax is wrong, a single = is to assign something to another thing, two == is to check if they are same, === three is for checking if they are of the same type as well as the values.
to convert the two to the same type, we can use the Number() Method as follows:
let maximum = prompt("Tell us your maximum number");
const targetNum = Math.floor(Math.random() * maximum) + 1
console.log(targetNum)
let guess = Number(prompt("Enter your first guess!"));
if (guess == targetNum) {
console.log("you win")
} else {
console.log("you lose")
}
This is the first app I have ever written. I have seen a million random number-generating games here, javascript and otherwise, but none had the problems I'm having. I apologize for my ignorance, but when I know what I'm doing wrong, this will go a long way toward my understanding of javascript and coding in general. I'm just playing in the browser console as of now.
I've done this with a for loop, but I wanted to try another option and use a decrement counter. I've tried using the if/else stuff from the inner function inside the while loop. The code looks right to me.
const guessingGame = (tries) => {
const answer = Math.floor(Math.random() * 11)
let guess = null
let status = "playing"
function makeGuess() {
if (guess === answer) {
status = "won"
} else if (tries === 0) {
status = "lost"
} else {
tries--
if (tries === 1) {
console.log(tries + ' guess left')
} else {
console.log(tries + ' guesses left')
}
}
}
while (status === "playing") {
if (!guess) {
guess = prompt('Guess a number between 1 and 10')
makeGuess()
} else if (guess > answer) {
guess = prompt('Lower')
makeGuess()
} else if (guess < answer) {
guess = prompt('Higher')
makeGuess()
} else {
break
}
}
console.log("Game Over. You " + status + "! The answer was " + answer + ".")
}
This game should invoke/launch with one argument, the number of tries allowed. If I correctly guess the answer, the console log at the end should include status = "won". But when I win, it includes status = "playing".
When I guess wrong "tries" number of times, I should lose. But when I see "0 guesses left" in the console, the game gives one more guess, and I can take it, effectively making tries -1, I think. When I make one additional wrong guess, status correctly changes to "lost" and the final console message is correct.
You checked tries === 0 before tries--, that's why you get 0 guesses left. You should decrement before checking.
The guess is actually a string not a number, so guess === answer never true. The next iteration after you guessed correctly, it falls into else{break} with the status still playing. You either want Number(guess) === answer or just guess == answer.
By Math.floor(Math.random() * 11) you are actually generating 0-10. You want Math.floor(Math.random() * 10) + 1 for 1-10. Just remember Math.floor(Math.random() * n) gives you n possible outcomes, which happens to be an integer in the range [0,n). Then do whatever calculation you want to map it to your desire output value.
const guessingGame = (tries) => {
const answer = Math.floor(Math.random() * 10) + 1
let guess = null
let status = "playing"
function makeGuess() {
tries--;
if (guess === answer) {
status = "won"
} else if (tries === 0) {
status = "lost"
} else {
if (tries === 1) {
console.log(tries + ' guess left')
} else {
console.log(tries + ' guesses left')
}
}
}
while (status === "playing") {
if (!guess) {
guess = Number(prompt('Guess a number between 1 and 10'))
makeGuess()
} else if (guess > answer) {
guess = Number(prompt('Lower'))
makeGuess()
} else if (guess < answer) {
guess = Number(prompt('Higher'))
makeGuess()
} else {
break
}
}
console.log("Game Over. You " + status + "! The answer was " + answer + ".")
}
guessingGame(5);
The result of prompt is a string; thus, guess is a string. The result of Math.floor is a number, so answer is a number.
> and < are coercing operators: if one of the operands is a number, the other is converted into the number, as well. This means guess < answer and guess > answer work as you hope it does.
However, you've apparently heard people say "never use ==, always use ===" and taken it to heart. The reason for the saying is == is also a coercing operator, and as a consequence sometimes things that don't look equal end up being equal. However, here you actually needed to use the coercing ==, because 1 == '1' (even though 1 and '1' are different types), but the strict 1 === '1' ends up being false!
Thus, you first check if guess is strictly equal to answer. Since their types are different, it is impossible, so you move on. You check if guess is above the answer, then you check whether it is below the answer, both of those return false as well. The only remaining option is to break from the loop - and "winner" never gets printed.
Beside this, your biggest problem is actually logic. The placement of different tests and actions is somewhat questionable. For example, one would expect that testing whether guess is equal to the answer would be right next to the test to see if it is bigger or smaller. The test for tries would be most at home right at the while loop; but you have an infinite loop, and an independent test for tries. You enter the first guess with a unique prompt, but it is inside an infinite loop, despite the fact it can only ever happen once. You have a function called makeGuess, but the function does two or three different things, none of which is actually making a guess.
Rather than start working on code right away, then fixing problems as they pop up, try to imagine first what the flow would be. How would a human do it? Then write code.
Here's the basic idea for the same game:
answer = imagineAnswer()
guess = askForFirstGuess()
status = "lost"
while (--tries) {
if (guess > answer) {
guess = askForHigherGuess()
} else if (guess < answer) {
guess = askForLowerGuess()
} else {
status = "won"
break
}
}
reportGameEnd(status)
I am trying to make a guessing game with simple java script. the professor gave us a guide, but i am still a bit confused. Based on the guide, we are to use a do/while loop, and within that loop, use the if/else if conditional statement, here is what i have so far.
i've tried changing it so many times, and all i end up with is a never ending loop, even after the number is guessed, it doesnt stop
<body>
<p>
I'm thinking of a number between 1 and 100, try to guess it! </br>
<script>
var number = Math.floor(Math.random() * 100 + 1)
//guess variable to store the guessed number by user
var guess
//output to store output to the user
var output
//if the user guessed the number or not, initialize it to false
var guessed = false
//do/while loop, while condition is based on if the user NOT guessing the number (e.g. guessed == false)
do {
guess = prompt ("Think of a number between 1 and 100, what is your number?");
document.write ("You guessed the number " + guess + "<br/>");
if (guess > number) {
document.write ("You guessed too high, think smaller" + "<br/>");
guessed = false
}
else if (guess < number){
document.write ("You guessed too low, think bigger" + "<br/");
guessed = false
}
else {
alert("You guessed the right number!")
guessed = true}
}
while (guessed = false)
</script>
</p>
</body>
You're missing a ton of semi-colons which should be added though your code will still run without them. And like everyone else said you are assigning guessed to false at the end of your do while loop, therefore it will never break out. To check a condition you should use 3 equal signs (this is strict comparison). More on that here. It is debatable if document.write should be used. Reason for that can be found here. Also, when testing your code it worked intermittently, so I added a div with the id of hints. Then I grabbed that element with var elHints = document.getElementById('#hints'); Then to add content to the element hints simply do elHints.textContent += .... The plus equals (+=) adds content to the element without overwriting existing content. In css I added a style to #hints: white-space: pre-line; this allows line breaks (\n) to the div when adding content using textContent. More on that here.
Here is the full javascript code:
var number = Math.floor(Math.random() * 100 + 1);
//guess variable to store the guessed number by user
var guess;
//output to store output to the user
var output;
//if the user guessed the number or not, initialize it to false
var guessed = false;
var elHints = document.getElementById('hints');
//do/while loop, while condition is based on if the user NOT guessing the number (e.g. guessed == false)
do {
guess = prompt("Think of a number between 1 and 100, what is your number?");
elHints.textContent += "You guessed the number " + guess + '\n';
if (guess > number) {
elHints.textContent += "You guessed too high, think smaller" + '\n';
guessed = false;
} else if (guess < number) {
elHints.textContent += "You guessed too low, think bigger" + '\n';
guessed = false;
} else {
alert("You guessed the right number!")
guessed = true;
}
}
while (guessed === false);
And here's the jsfiddle.
I believe that you are missing a semi-colon here :
while(guessed == false);
This is just an requirement specific to the do-while loop and does not occur in the syntax for other loops.
In your condition at while(guessed = false) you use one equal-signe (=), witch is forever true. you must write (guessed == false) or (guessed === false). for trying i would do ist so:
I'm thinking of a number between 1 and 100, try to guess it!
<script type="text/javascript">
var number = Math.floor(Math.random() * 100 + 1);
// Just for Test
document.getElementById('test').innerHTML += '<br />' + number;
//guess variable to store the guessed number by user
var guess;
//output to store output to the user
var output;
//if the user guessed the number or not, initialize it to false
var guessed = false;
//do/while loop, while condition is based on if the user NOT guessing the number (e.g. guessed == false)
do {
guess = prompt("Think of a number between 1 and 100, what is your number?");
document.getElementById('test').innerHTML += '<br />' + "You guessed the number " + guess;
if (guess > number) {
document.getElementById('test').innerHTML += '<br />' + "You guessed too high, think smaller";
guessed = false;
}
else if (guess < number) {
document.getElementById('test').innerHTML += '<br />' + "You guessed too low, think bigger";
guessed = false;
}
else {
alert("You guessed the right number!")
guessed = true;
}
}
while (guessed == false)
</script>
Your code has some issues.
First of all you need to change while (guessed = false) into while (guessed === false) because it should be a comparision, hence you have to use a comparator.
Secondly, you are using document.write(). This will not work, because the HTML won't change until the user breaks out of the loop. It would be a good idea to use alert() instead. Here is a working example:
var number = Math.floor(Math.random() * 100 + 1)
//guess variable to store the guessed number by user
var guess
//output to store output to the user
var output
//if the user guessed the number or not, initialize it to false
var guessed = false
//do/while loop, while condition is based on if the user NOT guessing the number (e.g. guessed == false)
do {
guess = prompt("Think of a number between 1 and 100, what is your number?");
if (guess > number) {
alert("You guessed too high, think smaller");
guessed = false
} else if (guess < number) {
alert("You guessed too low, think bigger");
guessed = false
} else {
alert("You guessed the right number!")
guessed = true
}
}
while (guessed === false)
I'm trying to write this program to find prime numbers. I have the basics of it down, except that no matter what number I put in, it returns as NOT prime. I've been messing with this for way too long and cannot figure out what it is. Is it in my "if" statement or my isPrime function? Please help, and thank you!
var number = 0;
function main()
{
number = parseInt(prompt("Please Enter a Number to Determine Whether or Not it is Prime:", "Enter a Number"));
while(isNaN(number) === true)
{ alert("You Entered an Invalid Number. Please Reenter");
number = parseInt(prompt("Please Enter a Number to Determine Whether or Not it is Prime:", "Enter a Number"));
}
isPrime(number);
if(prime = false)
{ alert("The number " + number + " is a Prime Number!"); }
else
{ alert("The number " + number + " is NOT a Prime Number!"); }
}
/*------------------------------------------------------*/
function isPrime(number)
{
if(number < 2)
{return false;}
var prime = false;
for(var i = 2; i <= Math.sqrt(number); i++)
{ if(number % i == 0)
{prime = true;}
}
return prime;
}
if (prime = false)
You just assigned prime to false.
You don't want to do that.
By contrast, you do want to assign it to the result of your function.
Replace:
if(prime = false)
not only because you're using assignment instead of comparison, but because prime is not defined (it's not going to return/create a global variable prime from that function call).
Replace it with:
if (!isPrime(number)) {
Now this doesn't use a variable to store the result of the isPrime call, but uses the call directly. If you need this result in more than one place, then it would be a good idea to assign it to a variable:
var prime = isPrime(number);
and then do the rest of your code:
if (prime == false)...
isPrime(number);
leaves no variable assigned. Therefore prime is never assigned in your test and unassigned variables are treated as false as far as boolean expressions are concerned.
It should be
var prime = isPrime(number);
You're also doing an assignment where you meant to do a comparison.
if(prime = false)
should be
if(prime === false)
Tip: If you're doing these kinds of tests, it's usually a good idea to put the thing that can't be changed by assignment on the left (function call, constant, etc). That way if you accidentally put = instead of == or === the script will fail with an error.
if(false === prime)
If you accidentally type
if (false = prime)
you'll get
ReferenceError: invalid assignment left-hand side
which is obvious and easy to debug.
As this is a simple boolean switch, a simple "is not true" check is fine.
if (!prime)
Actually their are only 2 small logic failure.
You define "prime" inside your function isPrime() - hence you cannot use it outside your function.
You try to do if(prime = false) which assigns the value false to "prime" whick does nothing for your if except breaking it.
You need to define the variable outside hence use your prime = isPrime()
Also you do not need to check against "false" which by any means does not really make sense their. "true == false" ? just skip that ans ask for if(prime) which is true or false.
Alternativly you can call your funtion directily in the if condition like:
if(isPrime(number)){....
it then automaticly checks the return value.