I'm trying to create a blackjack game, where the player starts off with 2 cards, and then asked if he/she would like to have another card (user input: yes or no), if yes, another card is added to the total. if no, the game just terminates.
Here is a sample output I'm trying to get:
And this is what I have so far (It's probably wrong in terms of the placement):
import java.util.Scanner;
public class BlackJackGame {
public static void main(String[] args) {
int randomnum1 = (int) (1 + Math.random() * 10);
int randomnum2 = (int) (1 + Math.random() * 10);
int randomnum3 = (int) (1 + Math.random() * 10);
int total;
char anotherCard = 'y';
Scanner input = new Scanner(System.in);
System.out.println("First cards: " + randomnum1 + ", " + randomnum2);
total = randomnum1 + randomnum2;
System.out.println("Total: " + total);
while (anotherCard != 'n')
{
System.out.print("Card: " + randomnum3);
System.out.print("Do you want another card? (y/n): ");
anotherCard = input.next().charAt(0);
}
}
}
Tips and reworking the source code will be highly appreciated.
As Far as card games go, there are 52 cards in a deck, and I'm assuming there's one deck.
If you want it to be a fair game, then you have to keep that in mind.
But if you just want output to look correct, you just have to avoid getting more than 4 aces, 2's, 3's, and 4's.
One way to achieve this would be to make an int array of size 52 with 4 of each card. I suppose Ace would be 1 and 10,J,Q,K would be 10, so there would be 16 10's.
Get a random number between 0 and 51 to get the index of the array you want to use. Once you use that index, set the value of that array = -1, and always check for -1 before using that index, and if it is -1, get another random value.
int [] deck = size 52 array with 4 of each card.
int random = get random number between 0 and 51.
while(deck[random] == -1){
random = get random number between 0 and 51.
}
int card1 = deck[random]
deck[random] = -1;
something like that.. I just did that quickly, hopefully you get the idea.
Here are the tips you requested:
You need to introduce a variable to keep track of your sum. For example, you could initialize it with: int sum = randomnum1 + randomnum2; and keep adding the next card to it inside the loop: sum += randomnum3;
You need to generate randomnum3 inside the while loop. This way, you will get a different card every time. Basically, you have to call the random function every time you generate a card, not just once. Otherwise the value of randomnum3 will be unchanged and you will get the same card over and over.
To exit when you get to 21, you would have to use if and possibly break within the loop, once you have added the current card to the sum: if(sum > 21) { break; }
Alternatively, you can set the value of anotherCard to 'n' instead of using a break
You should keep track of which cards the user has already gotten if you want to simulate an actual deck. This is not technically necessary for the program you appear to be writing though.
Here are a few simple improvements for you to look over. I'll leave it like this as part of the joy of learning to program is in the discovery. As a next step I'd suggest generating a dealers hand and then seeing if the player can beat it. Good luck!
public static void main(String[] args) {
int card1 = (int) (1 + Math.random() * 10);
int card2 = (int) (1 + Math.random() * 10);
int total = card1 + card2;
System.out.println(String.format("First cards: %d & %d. Total %d", card1, card2, total));
System.out.println();
Scanner input = new Scanner(System.in);
System.out.print("Do you want another card? (y/n): ");
char anotherCard = input.next().charAt(0);
while (anotherCard != 'n' && total < 21) {
int nextcard = (int) (1 + Math.random() * 10);
total += nextcard;
System.out.println(String.format("You drew a %d. Your total is now %d", nextcard, total));
if (total > 21) {
System.out.println("You busted!");
} else {
System.out.print("Do you want another card? (y/n): ");
anotherCard = input.next().charAt(0);
}
}
}
Related
I'm wondering if there was a way to create a random number generator that generates a number between two integers, but is twice as likely to generate an even number than an odd number. At current, I haven't come up with a way that's even similar or close to 2x as likely.
Simple but should work:
store random float call (0.0f - 1.0f) (random.nextFloat())
get a random integer in desired range
if random float call was less than 0.67f, if needed decrement or increment the random integer to make it even, return value
else, if needed decrement or increment the random integer to make it odd, return value
Make sure you decrement or increment towards the right direction if random integer is a boundary value of the desired range.
There are many ways you could do this. One would be to generate two integers: one between the user's bounds, and one between 0 and 2, inclusive. Replace the last bit of the first number with the last bit of the second number to get a result that is even twice as often as it is odd.
You do need to watch out for the possibility that the bit-twiddling last step puts the result out of bounds; in that event, you should re-draw from the beginning.
Implementing #SteveKuo 's suggestion in the comments:
import java.util.Scanner;
class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Please enter the minimum number that can be generated: ");
int min = scanner.nextInt();
System.out.print("Please enter the maximum number that can be generated: ");
int max = scanner.nextInt();
int evenOrOdd = 0 + (int)(Math.random() * ((2 - 0) + 1));
int random = 0;
if(evenOrOdd == 2) { // generate random odd number
if(max % 2 == 0) { --max; }
if(min % 2 == 0) { ++min; }
random = min + 2*(int)(Math.random() * ((max - min)/2+1));
} else { //get random number between [(min+1)/2, max/2] and multiply by 2 to get random even number between min and max
random = ((min+1)/2 + (int)(Math.random() * ((max/2 - (min+1)/2) + 1))) * 2;
}
System.out.printf("The generated random number is: %d", random);
}
}
Try it here!
Firstly, I'm taking AP Computer Science this year, and this question is related to an exercise we were assigned in class. I have written the code, and verified that it meets the requirements to my knowledge, so this is not a topic searching for homework answers.
What I'm looking for is to see if there's a much simpler way to do this, or if there's anything I could improve on in writing my code. Any tips would be greatly appreciated, specific questions asked below the code.
The exercise is as follows: Write a program called ProcessingNumbers that does:
Accepts a user input as a string of numbers
Prints the smallest and largest of all the numbers supplied by the user
Print the sum of all the even numbers the user typed, along with the largest even number typed.
Here is the code:
import java.util.*;
public class ProcessingNumbers {
public static void main(String[] args) {
// Initialize variables and objects
Scanner sc = new Scanner(System.in);
ArrayList<Integer> al = new ArrayList();
int sumOfEven = 0;
// Initial input
System.out.print("Please input 10 integers, separated by spaces.");
// Stores 10 values from the scanner in the ArrayList
for(int i = 0; i < 10; i++) {
al.add(sc.nextInt());
}
// Sorts in ascending order
Collections.sort(al);
// Smallest and largest values section
int smallest = al.get(0);
int largest = al.get(al.size() - 1);
System.out.println("Your smallest value is " + smallest + " and your largest value is " + largest);
// Sum of Even numbers
int arrayLength = al.size();
for (int i = 0; i < al.size(); i++) {
if (al.get(i) % 2 == 0) {
sumOfEven += al.get(i);
}
}
System.out.println("The sum of all even numbers is " + sumOfEven);
// Last section, greatest even number
if (al.get(arrayLength - 1) % 2 == 0) {
System.out.println("The greatest even number typed is " + al.get(arrayLength - 1));
} else {
System.out.println("The greatest even number typed is " + al.get(arrayLength - 2));
}
sc.close();
}
}
Here are specific questions I'd like answered, if possible:
Did I overthink this? Was there a much simpler, more streamlined way to solve the problem?
Was the use of an ArrayList mostly necessary? We haven't learned about them yet, I did get approval from my teacher to use them though.
How could I possibly code it so that there is no 10 integer limit?
This is my first time on Stackoverflow in quite some time, so let me know if anything's out of order.
Any advice is appreciated. Thanks!
Usage of the ArrayList wasn't necessary, however it does make it much simpler due to Collections.sort().
To remove the 10 integer limit you can ask the user how many numbers they want to enter:
int numbersToEnter = sc.nextInt();
for(int i = 0; i < numbersToEnter; i++) {
al.add(sc.nextInt());
}
Another note is that your last if-else to get the highest even integer doesn't work, you want to use a for loop, something like this:
for (int i = al.size() - 1; i >= 0; i--) {
if (al.get(i) % 2 == 0) {
System.out.println("The greatest even number typed is " + al.get(i));
break;
}
I wouldn't say so. Your code is pretty straightforward and simple. You could break it up into separate methods to make it cleaner and more organized, though that isn't necessary unless you have sections of code that have to be run repeatedly or if you have long sections of code cluttering up your main method. You also could have just used al.size() instead of creating arrayLength.
It wasn't entirely necessary, though it is convenient. Now, regarding your next question, you definitely do want to use an ArrayList rather than a regular array if you want it to have a variable size, since arrays are created with a fixed size which can't be changed.
Here's an example:
int number;
System.out.print("Please input some integers, separated by spaces, followed by -1.");
number = sc.nextInt();
while (number != -1) {
al.add(number);
number = sc.nextInt();
}
Here is a solution that:
Doesn't use Scanner (it's a heavyweight when all you need is a line of text)
Doesn't have a strict limit to the number of numbers
Doesn't need to ask how many numbers
Doesn't waste space/time on a List
Handles the case when no numbers are entered
Handles the case when no even numbers are entered
Fails with NumberFormatException if non-integer is entered
Moved actual logic to separate method, so it can be mass tested
public static void main(String[] args) throws Exception {
System.out.println("Enter numbers, separated by spaces:");
processNumbers(new BufferedReader(new InputStreamReader(System.in)).readLine());
}
public static void processNumbers(String numbers) {
int min = 0, max = 0, sumOfEven = 0, maxEven = 1, count = 0;
if (! numbers.trim().isEmpty())
for (String value : numbers.trim().split("\\s+")) {
int number = Integer.parseInt(value);
if (count++ == 0)
min = max = number;
else if (number < min)
min = number;
else if (number > max)
max = number;
if ((number & 1) == 0) {
sumOfEven += number;
if (maxEven == 1 || number > maxEven)
maxEven = number;
}
}
if (count == 0)
System.out.println("No numbers entered");
else {
System.out.println("Smallest number: " + min);
System.out.println("Largest number: " + max);
if (maxEven == 1)
System.out.println("No even numbers entered");
else {
System.out.println("Sum of even numbers: " + sumOfEven);
System.out.println("Largest even number: " + maxEven);
}
}
}
Tests
Enter numbers, separated by spaces:
1 2 3 4 5 6 7 8 9 9
Smallest number: 1
Largest number: 9
Sum of even numbers: 20
Largest even number: 8
Enter numbers, separated by spaces:
1 3 5 7 9
Smallest number: 1
Largest number: 9
No even numbers entered
Enter numbers, separated by spaces:
-9 -8 -7 -6 -5 -4
Smallest number: -9
Largest number: -4
Sum of even numbers: -18
Largest even number: -4
Enter numbers, separated by spaces:
No numbers entered
Problem statement
I have another thread on this, but I can't seem to locate it. Basically, I have a Black Jack game. The user is given two random cards (then those cards are added together, and display the total). Then it prompts user if they want another card (They pretty much will want to have a total lower than 21). If they choose "yes," they are given a random card number (they can keep getting a card, but should avoid going over 21), but if they choose "no," the game stops.
Here's the output I should get: [blackjackoutput.jpg]
And here's what I'm getting: [output1.jpg]
Source code:
public class BlackJackGame {
public static void main(String[] args) {
int randomnum1 = (int) (1 + Math.random() * 10);
int randomnum2 = (int) (1 + Math.random() * 10);
int total;
char anotherCard = 'y';
char playAgain;
Scanner input = new Scanner(System.in);
// Prints cards player starts off with
System.out.println("First cards: " + randomnum1 + ", " + randomnum2);
// Sum of the 2 cards
total = randomnum1 + randomnum2;
// Prints Total
System.out.println("Total: " + total);
// Do While Loop that asks question to get lower than 21 or terminate.
while (anotherCard != 'n') {
if (total <= 21) {
System.out.print("Do you want another card? (y/n): ");
anotherCard = input.next().charAt(0);
int randomnum3 = (int) (1 + Math.random() * 10);
System.out.println("Card: " + randomnum3);
total += randomnum3;
System.out.println("Total: " + total);
} else if (total > 21) {
System.out.println("BUST.");
System.out.print("Would you like to play again? (y/n): ");
playAgain = input.next().charAt(0);
}
}
}
}
Issue
When I reach to 21, I choose "no," to stop the program. But, it continues to display the next card and the updated total.
When I "BUST." (Or go over 21). It'll ask me if I want to play. And on separate occasions, I choose "y" and it says "Bust." and asks me if I want to play again (it loops, says "BUST.", and asks me the same question, without being able to end the program). Same thing if I choose "no" it'll say "Bust." and ask me if I can want to play again.
How do you play the game again?
PLEASE HELP!!!
The issue you have is a logic issue here:
if (total <= 21)
{
System.out.print("Do you want another card? (y/n): "); //<--------------
anotherCard = input.next().charAt(0);
int randomnum3 = (int) (1 + Math.random() * 10);
System.out.println("Card: " + randomnum3);
total += randomnum3;
System.out.println("Total: " + total);
You need to check if(anotherCard == 'n') to break out of the loop
Side Note
This blackjack game should have a better distribution of random cards better modeled off a 52 card deck
Okay so I changed my code around and deleted a lot of the unnecessary garbage in it. It works for some numbers but not for others, for example, when I put in 100 rolls/8 sides/3 die it gives me an out of bounds error despite the limits I've set for it. Obviously I've looked over some detail, I'm just not sure what detail it is.
public class Ass11f {
public static void main(String[] args) {
EasyReader console = new EasyReader();
System.out.print("Enter how many times you want to roll the die: ");
int numRolls = console.readInt();
System.out.print("Enter the amount of sides: ");
int numSides = console.readInt();
System.out.print("Enter the amount of die: ");
int numDie = console.readInt();
int[] rollSum = new int[numDie*numSides];
for (int i = 0; i<numRolls; ++i)
{
int rollCounter=0;
for (int l = 0; l<numDie; ++l){
rollCounter += ((int)(Math.random()*numSides)+1);
}
rollSum[rollCounter]++;
}
for (int m = 2;m<=rollSum.length;++m) System.out.println(m+"'s: "+rollSum[m]+" times, "+((((double)rollSum[m])/numRolls)*100)+"%");
}
}
There are two base problems:
When adding roll totals, you're trying to add the maximum roll in an index one past the end of the array. The easy fix is to simply add 1 to the length of your array.
When printing, you cannot access an array using an index equal to the array's length, which is what m<=rollSum.length will eventually do. Replace that with m < rollSum.length so it stops before the final value.
Also, here's some ways to make your array creation a bit clearer:
// The minimum value is always numDie.
// The maximum is always numDie * numSides
// There are maximum - minimum + 1 possible values (ie 6 on a d6)
int maximum = numDie * numSides;
int minimum = numDie;
// Remember, index zero is now the minimum roll.
// The final index is the maximum roll. So the count at an index is really
// the count for any roll with value index + minimum
int[] rollSum = new int[maximum - minimum + 1];
I also recommend splitting up that print statement. It's a bit easier to read and debug. Also, you can start at numDie instead of 2 to account for when you have more or less die than 3:
for (int i = numDie; i < rollSum.length; ++i) {
// Print the first bit, ie "2's: ".
System.out.print(i + "'s: ");
// How many times was that value rolled?
System.out.print(rollSum[i] + " times, ");
// What percentage is that?
double percentage = ((double)rollSum[i]) / numRolls * 100;
System.out.println(percentage + "%");
}
I am at the end of my homework, and a little confused on the right way to go for this algorithm. I need to find the base10 of a number:base that user gives.
Basically what my program does is take user input such as, 407:8 or 1220:5 etc.
What I am trying to output is like this.
INPUT: 407:8
OUTPUT: 407 base 8 is 263 base 10
I was thinking of this long stretched out way of doing it but I am sure there is a way easier way to go about it.
Attached is what i have so far. Thanks for looking!!
import javax.swing.JOptionPane; //gui stuff
import java.util.Scanner; // Needed for accepting input
import java.text.*; //imports methods for text handling
import java.lang.Math.*; //needed for math stuff*
public class ProjectOneAndreD //my class + program name
{
public static void main(String[] args) //my main
{
String input1; //holds user input
int val=0, rad=0, check1=0; //holds integer values user gives
and check for : handler
double answer1=0; //holds the answer!
Scanner keyboard = new Scanner(System.in);
//creates new scanner class
do //will continue to loop if no : inputted
{
System.out.println("\t****************************************************");
System.out.println("\t Loading Project 1. Enjoy! "); //title
System.out.println("\t****************************************************\n\n");
input1 = JOptionPane.showInputDialog("INPUT: ","EXAMPLE: 160:2"); //prompts user with msgbox w/ example
System.out.println("Program Running..."); //gives user a secondary notice that everything is ok..
check1=input1.indexOf(":"); //checks input1 for the :
if(check1==-1) //if no : do this stuff
{
System.out.println("I think you forgot the ':'."); //let user know they forgot
JOptionPane.showMessageDialog(null, "You forgot the ':'!!!"); //another alert to user
}
else //otherwise is they remembered :
{
String numbers [] = input1.split(":"); //splits the string at :
val = Integer.parseInt(numbers[0]); //parses [0] to int and assigns to val
rad = Integer.parseInt(numbers[1]); //parses [1] to int and assigns to rad
//answer1 = ((Math.log(val))/(Math.log(rad))); //mathematically finds first base then
//answer1 = Integer.parseInt(val, rad, 10);
JOptionPane.showMessageDialog(null, val+" base "+rad+" = BLAH base 10."); //gives user the results
System.out.println("Program Terminated..."); //alerts user of program ending
}
}while(check1==-1); //if user forgot : loop
}
}
You can use Integer.parseInt(s, radix).
answer = Integer.parseInt(numbers[0], rad);
You parse number in given radix.
It's easy, just replace your commented out logic with this:
int total = 0;
for (int i = 0; val > Math.pow(rad, i); i++) {
int digit = (val / (int) Math.pow(10, i)) % 10;
int digitValue = (int) (digit * Math.pow(rad, i));
total += digitValue;
}
and total has your answer. The logic is simple - we do some division and then modulus to pull the digit out of val, then multiply by the appropriate radix power and add to the total.
Or, if you want to make it a little more efficient and lose the exponentials:
int total = 0;
int digitalPower = 1;
int radPower = 1;
while (val > radPower) {
int digit = (val / digitalPower) % 10;
int digitValue = digit * radPower;
total += digitValue;
digitalPower *= 10;
radPower *= rad;
}
You only have implemented the user interface. Define a method taking two integers (the base and the number to convert) as argument, and returning the converted number. This is not very difficult. 407:8 means
(7 * 8^0) + (0 * 8^1) + (4 * 8^2)
You thus have to find a way to extract 7 from 407, then 0, and then 4. The modulo operator can help you here. Or you could treat 407 as a string and extract the characaters one by one and transorm each of them into an int.