如何将字符串输入与2D数组中的字符配对？

Question

When I run the method below keep in mind ADFGVX will be printed to the left and over the top of the array when its displayed, just like a classic ADFGVX cypher.

static char [][] poly = new char[][]{
        {'p','h','0','q','g','6'},
        {'4','m','e','a','1','y'},
        {'l','2','n','o','f','d'},
        {'x','k','r','3','c','v'},
        {'s','5','z','w','7','b'},
        {'j','9','u','t','i','8'}};

I have written a method that displays a polybius square using a 2d array(array can be seen above) and what I want to do is pair what ever the user enters with the square, so if the user types OBJECT I want it to return FG VX XA DF GV XG.

Scanner console = new Scanner (System.in);

String phrase;

displayGrid();
System.out.println("");

System.out.print("Please enter a phrase you want to use\n");
phrase = console.nextLine();

console.close();

Does anyone here know how I would go about this? I was going to make a switch statement or something but I don't think that would work and even if it did it would be very long and inefficient.

Answer 1

You could just iterate over your array to get the position of the character you are looking for and than decode this position to the letter.

public static String[] cypherADFGVX(String phrase){

    String[] output=new String[phrase.length()];

    for (int i = 0; i < phrase.length(); i++) {
        //optional for breaking
        //squareIteration:
        for (int j = 0; j < 6; j++) {
            for (int k = 0; k < 6; k++) {
                if(poly[j][k]==phrase.charAt(i)){
                    output[i]=new String(new char[]{switchChar(j),switchChar(k)});
                    //To stop the iteration over poly and take care of the next char
                    //break squareIteration;                    
                }
            }
        }
    }

    return output;
}

public static char switchChar(int integer){
    switch (integer) {
    case 0:     
        return 'A';
    case 1:
        return 'D';
    //and so on
    }
}

If I left any questions just ask.

To answer your questions

Oh. I see. I made it a bit too complicated for java beginners. An easier solution with just one String would be:

public static String cypherADFGVX(String phrase){

    String output=new String[phrase.length()];

    for (int i = 0; i < phrase.length(); i++) {
        //optional for breaking
        //squareIteration:
        for (int j = 0; j < 6; j++) {
            for (int k = 0; k < 6; k++) {
                if(poly[j][k]==phrase.charAt(i)){
                    output=output+switchChar(j)+switchChar(k)+" ";
                    //To stop the iteration over poly and take care of the next char
                    //break squareIteration;                    
                }
            }
        }
    }

    return output;
}

Now let me explain what my lines do.

String[] output=new String[phrase.length()];

creates a new array of string where each string are the two capital letters. It would look like ["FG","VX",...]. It is easier for futher processing in my opinion.

 if(poly[j][k]==phrase.charAt(i))

Compares the character at position jk in your square with the i-th character of the input String.

output[i]=new String(new char[]{switchChar(j),switchChar(k)});

I use the String constructor that takes a char-array as argument.

new char[]{'a','b'}

creates the array and fills it with the elements listed in the brackets.

Sure you can use the switch to set the value of a variable and than return that variable.