如何获取用户输入并将其显示在阵列上？

Question

I am creating an airplane seating chart. I am able to display the chart and can ask for user input. I am trying to take what they answer with and put "X" for where their input states. I don't know how to take their input and display it on the chart and then replace it with X.

import java.util.Scanner;

class AirplaneSeating {
public static void main(String[] args) {
  String[][] seatingChart = new String[10][4];
  int rows = 10;
  int columns = 4;

  Scanner inStr = new Scanner(System.in);

  seatingChart = new String[rows][columns];

  seatingChart[0][0] = "A1";
  seatingChart[0][1] = "A2";
  seatingChart[0][2] = "A3";
  seatingChart[0][3] = "A4";
  seatingChart[1][0] = "B1";
  seatingChart[1][1] = "B2";
  seatingChart[1][2] = "B3";
  seatingChart[1][3] = "B4";
  seatingChart[2][0] = "C1";
  seatingChart[2][1] = "C2";
  seatingChart[2][2] = "C3";
  seatingChart[2][3] = "C4";
  seatingChart[3][0] = "D1";
  seatingChart[3][1] = "D2";
  seatingChart[3][2] = "D3";
  seatingChart[3][3] = "D4";
  seatingChart[4][0] = "E1";
  seatingChart[4][1] = "E2";
  seatingChart[4][2] = "E3";
  seatingChart[4][3] = "E4";
  seatingChart[5][0] = "F1";
  seatingChart[5][1] = "F2";
  seatingChart[5][2] = "F3";
  seatingChart[5][3] = "F4";
  seatingChart[6][0] = "G1";
  seatingChart[6][1] = "G2";
  seatingChart[6][2] = "G3";
  seatingChart[6][3] = "G4";
  seatingChart[7][0] = "H1";
  seatingChart[7][1] = "H2";
  seatingChart[7][2] = "H3";
  seatingChart[7][3] = "H4";
  seatingChart[8][0] = "I1";
  seatingChart[8][1] = "I2";
  seatingChart[8][2] = "I3";
  seatingChart[8][3] = "I4";
  seatingChart[9][0] = "J1";
  seatingChart[9][1] = "J2";
  seatingChart[9][2] = "J3";
  seatingChart[9][3] = "J4";

  for(int i = 0; i < rows ; i++) {
    for(int j = 0; j < columns ; j++) {
       System.out.print(seatingChart[i][j] + " ");
    }
    System.out.println("");
  }

  System.out.println("What seat would you like to reserve? ");
  String str = inStr.nextLine();

  System.out.println("You chose: " + str);      

  }   
}

Answer 1

You just want to display any way? How do you want the input? Any way?

You can just parse the scanner input and tell the user put row, column just like your code.

//Example: Input: 6,2
//Split the user input
String[] input = str.split(",");
//parse first number to make it the row
int rowuser = Integer.parseInt(input[0].trim());
//parse second number to make it the column
int columnuser = Integer.parseInt(input[1].trim());
//replace with "X" value the seatingChart[row][column]
seatingChart[rowuser][columnuser] = "X"

but you will still need a loop to display the seating chart again.

Answer 2

Looking at the your program and the way the seats are structured, you can achieve this by simply parsing and storing the input.

char firstChar = str.toUpperCase().charAt(0);
char secondChar = str.charAt(1);
int first = ((int) firstChar) - 101; // ascii value - 101 for upper case A
int second = ((int) secondChar) - 1; // cast the character to an int, then -1 because it's 0 indexed.

Then all you have to do to set the value is is

seatingChart[first][second] = "X";

Then you can just print it out again.

Answer 3

Make sure str is two characters. Take the first character (I'm guessing it'll be a alphabetical char), convert it into a number, and store it as a variable (say, x). Do the same with the second character (say, y). set seatingChart[x][y] = "X" and then run your display loop again.

I hope this wasn't too specific of an answer since this is clearly homework.

Answer 4

Consider creating HashMap<Character, Integer> that maps row letters to the respective number. Given user input, take the first character and get the appropriate row index from your hash map. Use library functions to convert the second character to an int . Now you have indices into your array and can change the value in question.

Answer 5

This snippet could help

assumed that input is given as the seats are defined. eg: H4

Scanner sc = new Scanner(System.in);
String input = sc.nextLine();
int x = (int)input.charAt(0)-65; //since 'A' has ASCII value of 65
int y = (int)input.charAt(1)-49; //since '0' has ASCII value of 49
// update seatingChart[x][y]

Answer 6

You could initialize this

  seatingChart = new String[rows][columns];

  seatingChart[0][0] = "A1";
  seatingChart[0][1] = "A2";
  seatingChart[0][2] = "A3";
  seatingChart[0][3] = "A4";
  seatingChart[1][0] = "B1";
  seatingChart[1][1] = "B2";
  seatingChart[1][2] = "B3";
  seatingChart[1][3] = "B4";
  seatingChart[2][0] = "C1";
  seatingChart[2][1] = "C2";
  seatingChart[2][2] = "C3";
  seatingChart[2][3] = "C4";
  seatingChart[3][0] = "D1";
  seatingChart[3][1] = "D2";
  seatingChart[3][2] = "D3";
  seatingChart[3][3] = "D4";
  seatingChart[4][0] = "E1";
  seatingChart[4][1] = "E2";
  seatingChart[4][2] = "E3";
  seatingChart[4][3] = "E4";
  seatingChart[5][0] = "F1";
  seatingChart[5][1] = "F2";
  seatingChart[5][2] = "F3";
  seatingChart[5][3] = "F4";
  seatingChart[6][0] = "G1";
  seatingChart[6][1] = "G2";
  seatingChart[6][2] = "G3";
  seatingChart[6][3] = "G4";
  seatingChart[7][0] = "H1";
  seatingChart[7][1] = "H2";
  seatingChart[7][2] = "H3";
  seatingChart[7][3] = "H4";
  seatingChart[8][0] = "I1";
  seatingChart[8][1] = "I2";
  seatingChart[8][2] = "I3";
  seatingChart[8][3] = "I4";
  seatingChart[9][0] = "J1";
  seatingChart[9][1] = "J2";
  seatingChart[9][2] = "J3";
  seatingChart[9][3] = "J4";

Like this:

    String[][] seatingChart = new String[rows][columns];
    for(int i = 0; i < rows; i++) {
        for(int j = 0; j < columns; j++) {
            seatingChart[i][j] = "" + ((char)('A' + i)) + ((char)('1' + j));
        }
    }

And the answer to your question is that once you have their input line:

  System.out.println("What seat would you like to reserve? ");
  String str = inStr.nextLine();

Then you just need to iterate through the array, and find a match:

  for(int i = 0; i < rows ; i++) {
    for(int j = 0; j < columns ; j++) {
       if(seatingChart[i][j].equals(str)) {
           System.out.print("XX" + " ");
       } else {
           System.out.print(seatingChart[i][j] + " ");
       }
    }
    System.out.println("");
  }