Java for loop error

Question

I am trying to get user input for sortValues[] array using the for statement (enter character 1, enter character 2, etc).

However, when I execute this, the program will not allow me to enter for character 2, instead skipping directly to character 3, as seen below.

enter image description here

How to resolve this? The code is included below.

thanks!

static public void s_1d_char () {
            int counter=0;
            int x=0;
            c.print("How many characters? ");
            counter = readInt();

            char[] sortValues = new char[counter+1];

            for (x=1;x<=counter;x++) {
                    System.out.println("Enter character "+(x)+":");
                sortValues[x] = readChar();
            }
    }

readChar implementation (this is from a library):

public synchronized char readChar ()
{
char result, ch;

if (ungotChar != EMPTY_BUFFER)
{
    result = (char) ungotChar;
    ungotChar = EMPTY_BUFFER;
    return (result);
}

if (lineBufferHead != lineBufferTail)
{
    result = lineBuffer [lineBufferTail];
    lineBufferTail = (lineBufferTail + 1) % lineBuffer.length;
    return (result);
}

startRow = currentRow;
startCol = currentCol;
if (currentRow > maxRow)
{
    startRow++;
    currentCol = 1;
}

// Turn cursor on if necessary
consoleCanvas.setCursorVisible (true);

// Wait for a character to be entered
while (true)
{
    ch = getChar ();

    if (ch == '\n')
    {
    clearToEOL = false;
    if (echoOn)
        print ("\n");
    clearToEOL = true;
    lineBuffer [lineBufferHead] = '\n';
    lineBufferHead = (lineBufferHead + 1) % lineBuffer.length;
    break;
    }
    if (ch == '\b')
    {
    if (lineBufferHead == lineBufferTail)
    {
        consoleCanvas.invertScreen ();
    }
    else
    {
        int chToErase;

        lineBufferHead = (lineBufferHead + lineBuffer.length - 1) % lineBuffer.length;
        chToErase = lineBuffer [lineBufferHead];
        if (echoOn)
        {
        if (chToErase != '\t')
        {
            erasePreviousChar ();
        }
        else
        {
            int cnt;
            eraseLineOfInput ();
            cnt = lineBufferTail;
            while (cnt != lineBufferHead)
            {
            print (lineBuffer [cnt]);
            cnt = (cnt + 1) % lineBuffer.length;
            }
        }
        }
    }
    } // if backspace
    else if (ch == '\025')
    {
    if (echoOn)
    {
        eraseLineOfInput ();
    }
    lineBufferHead = lineBufferTail;
    }
    else
    {
    if (echoOn)
    {
        print (ch);
    }
    lineBuffer [lineBufferHead] = ch;
    lineBufferHead = (lineBufferHead + 1) % lineBuffer.length;
    }
} // while

result = lineBuffer [lineBufferTail];
lineBufferTail = (lineBufferTail + 1) % lineBuffer.length;

// Turn cursor on if necessary
consoleCanvas.setCursorVisible (false);

return (result);
}

I don't know if it is the case, which is why im' making comments and not answers, but you can check by just not pressing enter between chars — Sam I am says Reinstate Monica, Jul 10 '12 at 21:45
If you use a BufferedInputStream to wrap your input, you have a handy `readLine()` method. — SJuan76, Jul 10 '12 at 21:46
Does this also skip the fourth character? If it does, the enter key is outputting a newline character. — Chris Dargis, Jul 10 '12 at 21:58
Yes - it skips the fourth character and goes to fifth character, similar to image above — 01jayss, Jul 10 '12 at 21:59
@01jayss: Then perhaps you should show the code for the `readChar()` method. — Chris Dargis, Jul 10 '12 at 22:01
edited the question to include readChar() - it is from a library that we were instructed to use — 01jayss, Jul 10 '12 at 22:02
@01jayss: Were you also instructed to read character-by-character? — Chris Dargis, Jul 10 '12 at 22:03
@01jayss: Then you are better off using a method besides `readChar()`. Consider something like the answer below. — Chris Dargis, Jul 10 '12 at 22:06
@DougRamsey i try using sortValues[x] =System.console().readLine().charAt(0);, however now the program will not allow me to enter a character... Enter character 1 shows up, but it will not allow me to input anything... — 01jayss, Jul 10 '12 at 22:08

score 1 · Answer 1 · edited May 23 '17 at 10:30

1

instead of readChar() try:

sortValues[x] = Integer.parseInt(System.console().readLine());

How to read integer value from the standard input in Java

edited May 23 '17 at 10:30

Community

1
1

answered Jul 10 '12 at 21:45

J Max

2,245
2
23
42

this only works for getting an integer... im trying to get a "char" value – 01jayss Jul 10 '12 at 21:49
1

@01jayss try maybe `char c=System.console().readLine().charAt(0)` – Pshemo Jul 10 '12 at 21:51
A char can be represented by an int. See [docs](http://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html). It's a 16-bit int, essentially, whereas the int data type is 32-bit. – Roddy of the Frozen Peas Jul 10 '12 at 22:22
@01jayss, what Roddy said, so long as you store it in a char (and maybe give it a cast), Java will automatically display it as a char. – ardent Jul 11 '12 at 06:46

Chris Dargis · Accepted Answer · 2012-07-11T00:18:03.157

1

I recommend getting user input with a scanner:

import java.util.Scanner;

// ...
int counter = 0;

System.out.println("How many characters?");
Scanner keyboard = new Scanner(System.in);
counter = keyboard.nextInt();

char[] sortValues = new char[counter+1];

// Start your index variable off at 0
for (int x = 0; x < counter; x++) { 
  System.out.println("Enter character "+(x)+":");
  keyboard = new Scanner(System.in);
  String line = keyboard.nextLine();
  sortValues[x] = line.charAt(0);
}

This will capture the first character of the line. If the user enters more than one character, the program will read only the first. Also, you should really start your index variable x off at 0, considering arrays are 0-based indexed.

edited Jul 11 '12 at 00:18

answered Jul 10 '12 at 22:15

Chris Dargis

5,203
3
33
59

thanks for your response. I have implemented your code, however, the program now stops after "How many characters" (it does not display Enter character, etc)...do you know the solution? – 01jayss Jul 10 '12 at 22:20
@01jayss: I updated the code snippet with a working solution. – Chris Dargis Jul 10 '12 at 23:55

Java for loop error

2 Answers2