Thread: array question

Adding 2 char's doesn't concatenate them into a string, it adds their underlying numerical representations.

To concatenate the two you need to use strings.

System.out.println("" + hhh[1][1] + hhh[1][1]); // kind of a cheater way to get strings, but it's quite commonly used

Originally Posted by thirddigit

... learning about arrays...
...
i think this should output d d
but instead it outputs 200
...

The result is not some peculiar quirk of arrays. It is a function of how println() works with numerical values and with Strings connected to numerical values with '+'

Here: I'll do a few examples using a simple char variable instead of an array:

// Notes about println with characters and numerical
// expressions involving characters.
//
//   Zaphod_b
//
public class Z {
    public static void main(String [] args) {
        char ch = 'd';
        int intch = (int)ch;
 
        System.out.println("The (integer) numerical value of ch is " + intch);
 
        System.out.println("\nWith \"println(ch)\", you get the character: ");
        System.out.println(ch);
 
        System.out.println("\nWith \"println((int)ch)\", you get the integer value of the character: ");
        System.out.println((int)ch);
 
        System.out.println("\nWhen you add a character to another character, the characters are");
        System.out.println("\"promoted\" to integers, and integer arithmetic is used to obtain");
        System.out.println("an integer result.");
 
        System.out.println("\nSo...");
 
        System.out.println("\nWith \"println(ch+ch)\", it prints the integer value of the expression:");
        System.out.println(ch+ch);
 
        System.out.println("\nHowever...");
        System.out.println("\nWhen you print a String + a character, it appends the character to the String.");
        System.out.println("With \"println(\"ch + ch = \" + ch + ch)\", here's the result:");
        System.out.println("ch + ch  = " + ch + ch);
 
        System.out.println("\nYou can even use an empty String to force character output to be characters.");
        System.out.println("With \"println(\"\" + ch + ch)\", you get this:");
        System.out.println("" + ch + ch);
    }
}

Output:

The (integer) numerical value of ch is 100

With "println(ch)", you get the character:
d

With "println((int)ch)", you get the integer value of the character:
100

When you add a character to another character, the characters are
"promoted" to integers, and integer arithmetic is used to obtain
an integer result.

So...

With "println(ch+ch)", it prints the integer value of the expression:
200

However...

When you print a String + a character, it appends the character to the String.
With "println("ch + ch = " + ch + ch)", here's the result:
ch + ch = dd

You can even use an empty String to force character output to be characters.
With "println("" + ch + ch)", you get this:
dd




Cheers!

Z