I'm doing lottery game for my assignment (user inputs 6 number, i will generate 8 unique winning numbers and 2 last numbers are supplementary). I need help with user input checking if input numbers are from 1 to 45 and input must be int, when input is not integer it throws an error.
This programming way is procedure way, how can i change it into object oriented way? I know that I must make methods in another java file and then link it back to this main. Can you suggest me how to do it?
I have tried try and catch, if and else (for input check) but i don't know how to check user input when it's in array. Thank you for help.
Here is my code:
class Lottery {
public static void main ( String[] args ) {
System.out.println("\nWelcome to the Lottery game.");
System.out.println("You can enter numbers from 1 to 45.");
// User input into an array
int[] input = new int[6];
Scanner scanner = new Scanner(System.in);
System.out.println("\nPlease enter your 6 lucky numbers: ");
for(int j = 0; j < 6; j++) {
input[j]=scanner.nextInt();
}
int check = scanner.nextInt();
if(check < 0 && check > 45) {
System.out.println("\nERROR: Please enter only numbers from 1 to 45!");
}
// Printing out unique winning numbers from random generator
System.out.println("\nWinning numbers: ");
MultiRandomGenerator mrg = new MultiRandomGenerator();
int[] set;
set = mrg.getSet();
for (int i = 0; i < set.length; i++) {
System.out.print(set[i] + " ");
}
// Loops for counting how many numbers user has guessed right
int count = 0; // for 6 numbers
int scount = 0; // for 2 last supplementary numbers
for(int i = 0; i < input.length; i++) {
for(int k = 0; k < set.length; k++) {
if (k < 6) {
if (set[k] == input[i]) {
count++;
} else {
if (set[k] == input[i]) {
scount++;
}
}
}
}
}
System.out.print("\n\nYou guessed right " + count + " winning numbers.");
System.out.print("\nYou guessed right " + scount + " suplementary numbers.");
// If statments for printing out winning prizes
if (count == 6) {
System.out.println("\nYou have won 1st price!");
} if (count == 5 && scount == 1) {
System.out.println("\nYou have won 2st price!");
} if (count == 5) {
System.out.println("\nYou have won 3st price!");
} if (count == 4) {
System.out.println("\nYou have won 4st price!");
} if (count == 3 && scount == 1) {
System.out.println("\nYou have won 5st price!");
} if (count == 1 && scount == 2) {
System.out.println("\nYou have won 6st price!");
} else {
System.out.println("\nSorry, you didn't won anything.");
}
}
}
Sample code to go through array and find the invalid user input.
set = mrg.getSet();
String[] userDataStatus = new String[45];
for (int i = 0; i < set.length; i++)
{
try
{
String inputdata = set.get(i);
if(inputdata != null && inputdata.trim().length() > 0)
{
int currentNumber = Integer.parseInt(userdata);
userDataStatus[i] = "Y";//Y represent valid number
}
}
catch (NumberFormatException ex )
{
userDataStatus[i] = "N";//If it throws exception then save as 'N'
}
}
Use the above String array and display error messaage to users.
You can check in your loop, something like
int val;
try
{
input[j] = Integer.parseInt( scanner.nextString() );
}
catch (NumberFormatException ex )
{
}
Related
package Demo;
import java.util.Scanner;
public class seat_reservation{
public static void main(String[] args) {
Scanner read = new Scanner(System.in);
// Initialization
final int ROWS = 2;
final int COLS = 3;
char [][] seats = new char [ROWS][COLS];
int i, j, seatNum, counter = 0;
char seatLetter = 'A';
int choice = 0;
String seatEnter;
boolean cont = true; // loops of running the program
while( choice != 4 ){
System.out.print( "1. Assign Seats" );
System.out.print( "2. Exit" );
System.out.print( "Select your choice: " );
choice = read.nextInt();
switch( choice ){
case 1:
//Set the value.
for (i=0; i < seats.length; i++) {
for (j=0; j < seats[i].length; j++)
seats[i][j] = seatLetter++;
seatLetter = 'A'; // to reset the value to A for the new loop
}
//To display the list of seats
for (i=0; i < seats.length; i++) {
System.out.print((i+1)+" ");
for (j=0; j < seats[i].length; j++)
System.out.print(seats[i][j]+" ");
System.out.println();
}
//condition
while (counter < 6 && cont) {
do {
System.out.print("Please type the chosen seat(starts with row and column,e.g:2A):" + "");
seatEnter = (read.nextLine()).toUpperCase(); //covert to Upper case
seatNum = Integer.parseInt(seatEnter.charAt(0)+"");
if (seatNum != 0)
seatLetter = seatEnter.charAt(1);
i++;
//if user enters wrong input, error message will appear.
if (seatLetter!='A'){
if (seatLetter!='B'){
if(seatLetter!='C'){
if(seatLetter!='D')
System.out.println ("Invalid! Please enter the correct seat:");
}
}
}
}
//continue to loop until the condition true
while (seatNum < 0 || seatNum > 7 || seatLetter < 'A' || seatLetter > 'D');
if (seatNum == 0) {
cont = false;
} else {
if (seats[seatNum-1][seatLetter-65] == 'X')
System.out.println("Seat have been taken.Please choose another seat:");
else {
seats[seatNum -1][seatLetter-65] = 'X';
counter++;
}
// To display updated lists of seats
for (i=0; i < seats.length; i++) {
System.out.print((i+1)+" ");
for (j=0; j < seats[i].length; j++)
System.out.print(seats[i][j] + " ");
System.out.println();
}
System.out.println(" ") ;
//}
//}
// displays fully booked message
if (counter == 6)
System.out.println("All seats are now fully-booked.");
break;
}
}
case 2://syntax error here
if (counter == 6)
System.out.println( "All seats are now fully-booked." );
System.out.println( "End of Program" );
System.exit(0);
break;
default:
System.out.println("Error input");
break;//syntax error here as well.
}
}
}
}
The problem is caused due to:
choice = read.nextInt();
The scanner.nextInt() only takes the next token from the input. Rest are ignored by it.
So when you're trying to take the next input from this line and process it, the error occurs:
seatEnter = (read.nextLine()).toUpperCase(); //covert to Upper case
seatNum = Integer.parseInt(seatEnter.charAt(0) + "");
As the previous read.nextInt() left the rest except first token, when you hit enter after giving 1 as input, it took only the 1 and the enter or newline token was captured by the read.nextLine(). That is why it got no charAt(0) and thus thrown StringIndexOutOfBoundException.
Try:
choice = Integer.parseInt(read.nextLine());
or,
choice = read.nextInt();
read.nextLine(); // this will capture the residue
Read whole numbers from a user, then display the list of numbers input and the frequency of each value. The number of inputs should vary from 1-30, and the values accept 0-9.
My issue is that the array always defaults to 1 even if I change it to int[] numbers = new int[numInputs];. It appears that numInputs gets written over to 1 during the first for loop but even changing the value of numInputs it still caps out at 1. I'm sure my logic is wrong but I'm not sure where.
public class Occurrence
{
public static void main(String[] args)
{
//variables
Scanner keyboard = new Scanner(System.in);
int numInputs = 1, temp;
int[] numbers = new int[31];
int[] count = new int[31];
boolean success = false;
//start of program
System.out.println("How many input values [max:30]?");
//while no valid input
while (!success)
{
try
{
numInputs = keyboard.nextInt(); //get a number
numInputChecker(numInputs); //is it valid?
success = true; //ok
}
catch (Exception e) //else get a new number
{
keyboard.nextLine();
System.out.println("Whole numbers 1 through 30 only, please.");
}
}
//reset the loop checker
success = false;
//read numbers to fill that array
System.out.println("Enter " + numInputs + " numbers.");
for(int i = 0; i < numInputs; i++) //from 0 to max number
{
while (!success) //while no valid number
{
try
{
numbers[i] = keyboard.nextInt(); //fill the current cell with a number
numberChecker(numbers[i]); //is it valid?
success = true; //ok
}
catch (Exception e) //else get a new number
{
keyboard.nextLine();
System.out.println("Whole numbers 0 through 9 only, please.");
}
}
}
//take the input and count each use of element
for (int i = 0; i< numbers.length; i++) //for 0 to max number
{
temp = numbers[i]; //get the current value of the cell
count[temp]++; //add the use of that value to a new array's cell
}
for(int i = 0; i < count.length; i++) //from 0 to 9 (expected)
{
if (count[i] > 0 && count[i] == 1) //if cell not empty
{
System.out.println(i + " " + count[i]); //print the current cell and how many times it was used
}
}
}
static void numInputChecker(int integer) throws Exception
{
if ((integer < 1) || (integer > 30)) //if 0 or negative, or if 31+
{
throw new Exception(); //say no
}
}
static void numberChecker(int integer) throws Exception
{
if ((integer < 0) || (integer > 9)) //if negative or 10+
{
throw new Exception(); //say no
}
}
}
The logic is broken at the second cycle where you do feel up an array, because success variable isn't reset for a subsequent while loops. It's quite easy to fix it as such:
for (int i = 0; i < numInputs; i++) //from 0 to max number
{
while (!success) //while no valid number
{
try {
numbers[i] = keyboard.nextInt(); //fill the current cell with a number
numberChecker(numbers[i]); //is it valid?
success = true; //ok
} catch (Exception e) //else get a new number
{
keyboard.nextLine();
System.out.println("Whole numbers 0 through 9 only, please.");
}
}
success = false; // [amsilf]: That's the cycle reset
}
Probably, java.util.NoSuchElementException occurs and catches the error handling the block.
Use keyboard.hasNextInt() before keyboard.nextInt().
Like this!
try {
keyboard.hasNext(); // here!
numInputs = keyboard.nextInt(); //get a number
numInputChecker(numInputs); //is it valid?
success = true; //ok
}
...
In the last for loop should be that
for(int i = 0; i < count.length; i++) //from 0 to 31(expected)
{
if (count[i] > 0) //if cell not empty
{
System.out.println(i + " " + count[i]); //print the current cell and how many times it was used
}
}
I am making a movie guessing game(much like hangman but doesn't contain the stick figure and stuff) on Java that takes input from the user, letter by letter. I am stuck where I want the letter entered to replace all instances of that letter in the title of the movie. My code is not working completely.
Later, I am gonna apply the logic that stops the user from entering the same letter again. But at the moment I need to fix this particular issue. Any help?
This is the game process function in my game class.
public void GameProcess(char[] dashedarray) {
Scanner input = new Scanner(System.in);
char guess;
int i = 0;
int spaces = 0;
int correct = 0;
int wrong = 0;
boolean run = true;
while (run) {
if (dashedarray[i] == ' ') {
spaces++;
i++;
continue;
} else {
System.out.println("Enter your guess.");
guess = input.next().charAt(0);
for (int j = 0; j < dashedarray.length; j++) {
if (dashedarray[j] != ' ') {
if (moviename.charAt(i) == guess) {
dashedarray[i] = guess;
correct++;
}
else if(moviename.charAt(j) == guess) {
dashedarray[j] = guess;
correct++;
}
}
else
{
wrong++;
}
}
i++;
PrintArray(dashedarray);
if (correct == (moviename.length() - spaces)) {
System.out.println("You have won.");
break;
} else if (wrong == 10) {
System.out.println("You have lost.");
break;
}
System.out.println("The number of wrong guesses is " + wrong + ".");
}
}
You don't need i at all. spaces is to count the number of spaces in your answer, which does not need to be guessed. You should do that outside of the loop.
Scanner input = new Scanner(System.in);
char guess;
int i = 0;
int spaces = 0;
int correct = 0;
int wrong = 0;
boolean run = true;
for (int i = 0; i < dashedarray.length; i++) {
spaces++;
}
while (run) {
System.out.println("Enter your guess.");
guess = input.next().charAt(0);
boolean match = false;
for (int j = 0; j < dashedarray.length; j++) {
if (dashedarray[j] != ' ') {
if(moviename.charAt(j) == guess) {
dashedarray[j] = guess;
correct++;
match = true;
}
}
}
// It matched nothing, this input is wrong.
if (!match) {
wrong++;
}
PrintArray(dashedarray);
if (correct == (moviename.length() - spaces)) {
System.out.println("You have won.");
break;
} else if (wrong == 10) {
System.out.println("You have lost.");
break;
}
System.out.println("The number of wrong guesses is " + wrong + ".");
}
I am having a problem with my java battleship program not printing the coordinates that the user enters. When the user guesses a spot on the board its supposed to update the space with an "X" if its a hit, if not then the board remains the same. But when a user guesses wrong on my program, it prints everything except the space where the user guessed. I believe that my else statement where the board updates is the problem, but any modification I did resulted in the board not printing anything.
import java.util.Random;
import java.util.Scanner;
class Battleship {
public static char randChar(){
final String alphabet = "ABCDE";
final int N = alphabet.length();
char rand;
Random r = new Random();
rand = alphabet.charAt(r.nextInt(N));
return rand;
}
public static void main (String[] args) throws java.lang.Exception {
char[] letters = {' ', 'A', 'B', 'C', 'D', 'E'};
int[] numbers ={1, 2, 3, 4, 5};
int[][] ships = new int[7][2];
char colGuess;
int rowGuess;
Boolean boardFlag=false;
Scanner scan = new Scanner(System.in);
//creates the board
for (int i = 0 ; i <= 5 ; i++) {
for (int j = 0 ; j <= 5 ; j++) {
if (i == 0) {
System.out.print(letters[j] + " ");
}
else if (j == 0) {
System.out.print(numbers[i - 1]);
}
else {
System.out.print(letters[j] + "" + numbers[i-1]);
}
System.out.print(" ");
}
System.out.println();
}
//assigns ships to random spots
assignShips(ships);
System.out.println("Enter your guess for the column:");
colGuess = scan.next().charAt(0);
//converts to uppercase
colGuess = Character.toUpperCase(colGuess);
System.out.println("Enter your guess for the row:");
rowGuess = scan.nextInt();
//shows player what they entered
System.out.println("you entered: " + (char) colGuess + rowGuess);
//calls method to check for a hit
fire(colGuess, rowGuess, ships);
boardFlag = fire(colGuess, rowGuess, ships);
System.out.println(boardFlag);
//updates the board
for (int i = 0 ; i <= 5 ; i++) {
for (int j = 0 ; j <= 5 ; j++) {
if (i == 0) {
System.out.print(letters[j] + " ");
}
else if (j == 0) {
System.out.print(numbers[i - 1]);
}
else {
if(letters[j] == colGuess && numbers[i - 1] == rowGuess) {
if(boardFlag==true) {
System.out.print(" " + "X");
}
}
else {
System.out.print(letters[j] + "" + numbers[i - 1]);
}
}
System.out.print(" ");
}
System.out.println();
}
}
public static void assignShips(int[][] ships) {
Random random = new Random();
for(int ship = 0; ship < 7; ship++) {
ships[ship][0] = randChar();
ships[ship][1] = random.nextInt(5);
//gives location of ships, for testing purposes
System.out.print("Ship:" + (ship+1)+ " is located at"+(char)ships[ship][0]+ships[ship][1]+"\n");
}
}
//checks user input to see if we have a hit
public static Boolean fire(char colGuess, int rowGuess, int[][] ships) {
Boolean hitFlag=false;
for(int ship = 0; ship < ships.length; ship++){
if(colGuess ==ships[ship][0] && rowGuess == ships[ship][1]){
hitFlag=true;
}
}
if(hitFlag == true) {
System.out.println("we hit em at "+(char)colGuess+rowGuess+" chief!");
}
else {
System.out.println("sorry chief we missed em");
}
return hitFlag;
}
}
The reason its not showing up when you miss is because your net telling it to print anything.
if(letters[j] == colGuess && numbers[i-1] == rowGuess){
if(boardFlag==true) {
System.out.print(" "+"X");
}
}
Your only handling the coordinate the user input if they hit. To fix this you would need an else statement after your if(boardFlag == true)to handle printing if you miss.
The problem is in your update board portion of the code because you don't do anything if the guessed location isn't a hit.
if(letters[j]==colGuess && numbers[i-1]==rowGuess && boardFlag) {
System.out.print(" "+"X");
} else {
System.out.print(letters[j]+""+numbers[i-1]);
}
Full Update Portion:
//updates the board
for (int i = 0 ; i <= 5 ; i++){
for (int j = 0 ; j <= 5 ; j++){
if (i == 0) {
System.out.print(letters[j]+" ");
} else if (j == 0){
System.out.print(numbers[i-1] );
} else {
if(letters[j]==colGuess && numbers[i-1]==rowGuess && boardFlag){
System.out.print(" "+"X");
} else {
System.out.print(letters[j]+""+numbers[i-1]);
}
}
System.out.print(" ");
}
System.out.println();
}
This block (old version):
if(hitFlag==true){
System.out.println("we hit em at "+(char)colGuess+rowGuess+" chief!");
} else {
System.out.println("sorry chief we missed em");
}
Should be (new version):
if(hitFlag==true){
System.out.println("we hit em at "+(char)colGuess+rowGuess+" chief!");
} else {
System.out.println("sorry chief we missed em at " + (char)colGuess+rowGuess);
}
this will print:
sorry chief we missed em at D3 //D3 is a random possible set of coordinates
Rather than:
sorry chief we missed em //Old version
So all you have to add is (char)colGuess+rowGuess, which prints the coordinates of your previous guess.
Comment if you have any questions!
I'm doing a simple cinema booking system. Here's the code that I've done so far. I'm a beginner and I'm pretty sure there are some flaws or bad coding practices in my code so please pardon me and correct me if you would like to.
I wanna ask that how can I modify the booked seats from integer to "**" and display it on the seating plan when the second loop of the whole program is executed so that the customers are able to see which seats have been booked? For example, a customer has booked seat 5, and he/she wants to book more, so when the second loop comes, he/she is able to see seat 5 has become **, which means it has been booked. I want to do this using array since I'm learning it, but I appreciate too if you have other methods than using array.
import java.util.Scanner;
public class CinemaBooking {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int[] SeatNo = new int[30];
int Seats;
int YesOrNo = 1;
String CustomerName;
while (YesOrNo == 1) {
System.out.print("Welcome to Crazy Cinema!\nWhat is your name?\n");
CustomerName = input.nextLine();
System.out.printf("Welcome %s! Please have a look at the seating plan.\n\n", CustomerName);
for (int i = 1; i <= 34; i++) {
System.out.print("*");
}
System.out.println();
System.out.print(" CINEMA 1 SEATING PLAN");
System.out.println();
for (int j = 1; j <= 34; j++) {
System.out.print("*");
}
System.out.println();
for (int SeatCounter = 0; SeatCounter < SeatNo.length; SeatCounter++) {
System.out.printf(SeatCounter + "\t");
if (SeatCounter == 4) {
System.out.println();
} else if (SeatCounter == 9) {
System.out.println();
} else if (SeatCounter == 14) {
System.out.println();
} else if (SeatCounter == 19) {
System.out.println();
} else if (SeatCounter == 24) {
System.out.println();
} else if (SeatCounter == 29) {
System.out.println();
}
}
for (int k = 1; k <= 34; k++) {
System.out.print("*");
}
System.out.println();
System.out.print("Which seat would you like to book? ");
Seats = input.nextInt();
while (Seats < 0 || Seats > 29) {
System.out.println("Only 0 - 29 seats are allowed to book. Please try again: ");
Seats = input.nextInt();
}
for (int SeatCounter = 0; SeatCounter < SeatNo.length; SeatCounter++) {
if (SeatCounter == Seats) {
System.out.println("Seat " + Seats + " is successfully booked.");
System.out.println(
"Thanks for booking!\n\nWould you like to make next booking? (Type 1 = Yes; Type 2 = No)");
YesOrNo = input.nextInt();
if (YesOrNo == 2) {
System.out.println("Thank you for using this program.");
}
}
}
while (YesOrNo != 1 && YesOrNo != 2) {
System.out.println("Invalid input.");
System.out.println("Type 1 = Continue booking; Type 2 = Exit the program");
YesOrNo = input.nextInt();
if (YesOrNo == 2) {
System.out.println("Thank you for using this program.");
}
}
}
}
}
One suggestion for you.
if ( SeatCounter == 4)
else if ( SeatCounter == 9)
else if ( SeatCounter == 14 )
...
You have used too many if else statements here. You could use single statement like this
if( (SeatCount+1) % 5 == 0 )
This will minize your code and make it somewhat simpler.