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Prompt the user to select one of four patterns

Posted on 2004-09-30
18
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Last Modified: 2010-03-31
I asked to prompt the user to select one of 4 patterns and display the pattern selected. How do I prompt the user which one to choose from, (either Pattern I or Pattern II)?

<code>


public class Pattern {
  public static void main(String[] args) {
    final int NUM_OF_LINES = 6;
   
    for (int row = 1; row <= NUM_OF_LINES; row++) {
   
      for (int num = 2; num <= row; num++)
        System.out.print(num);

        for (int column = 1; column <= NUM_OF_LINES - row; column++)
        System.out.print(" ");
       
     
      System.out.println();
    }
   
   
    for (int row = 1; row <= NUM_OF_LINES; row++) {
   
      for (int column = 1; column <= NUM_OF_LINES - row; column++)
        System.out.print(" ");

     
      for (int num = 2; num <= row; num++)
        System.out.print(num);

       
     
      System.out.println();
    }
   
  }
}
0
Comment
Question by:biloonline
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18 Comments
 

Author Comment

by:biloonline
ID: 12197024
for (int num = 2; num <= row; num++) should be (int num = 1; .... )
0
 
LVL 6

Expert Comment

by:expertmb
ID: 12197053
use

System.in.read()
0
 

Author Comment

by:biloonline
ID: 12197072
I know how to input an answer from the user, in my case( Pattern I, Pattern II), but how would the program know what to display, whether Pattern I or II?
0
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Author Comment

by:biloonline
ID: 12197100
Also how can I construct a for loop to display the following pattern:
         1
       21
     321
   4321
  54321
654321


Thanks
0
 
LVL 3

Expert Comment

by:CI-Ia0s
ID: 12197115
You could also use JOptionPane.

At the top of your class file put "import javax.swing.JOptionPane;"

Code:

String inString = JOptionPane.showInputDialog("Some text to display telling the user what to enter.");

/*At this point you can just check if they entered the right string. In the "Some text to display..." area you should tell them what the possible inputs are.*/

if (inString.equals("Pattern 1")){//Do Pattern 1
}
else if (inString.equals("Pattern 2")){//Do Pattern 2
}
else if (inString.equals("Pattern 3")){//Do Pattern 3
}
else if (inString.equals("Pattern 4")){//Do Pattern 4
}
else{JOptionPane.showMessageDialog(null, "Bad input.");}
0
 

Author Comment

by:biloonline
ID: 12197117
Disregard the last question, I got it.
0
 

Author Comment

by:biloonline
ID: 12197124
CI-Ia0s,

I am asked to use:

BufferedReader stdin  = new BufferedReader (new InputStreamReader(System.in));

Thanks
0
 
LVL 6

Expert Comment

by:expertmb
ID: 12197128
int number = 0;      
try{
          number = System.in.read();
      }catch(Exception ex){
      }

if((char)number == '1'){
// first pattern
}else if((char)number == '2'){
//pattern 2
}
0
 
LVL 6

Accepted Solution

by:
expertmb earned 125 total points
ID: 12197133
public class Pattern1 {
  public static void main(String[] args) {
    System.out.println("Select Pattern 1 or 2, or 3 to exit the application");

    System.out.println("Read pattern ");

      int number = 0;
      try{
          number = System.in.read();
      }catch(Exception ex){
      }

    System.out.println("Pattern: " + (char)number);

    final int NUM_OF_LINES = 6;

          if((char)number == '1'){
            for (int row = 1; row <= NUM_OF_LINES; row++) {

              for (int num = 2; num <= row; num++)
                  System.out.print(num);

               for (int column = 1; column <= NUM_OF_LINES - row; column++)
                  System.out.print(" ");


              System.out.println();
            }
      }else if ((char)number == '2'){

            for (int row = 1; row <= NUM_OF_LINES; row++) {

              for (int column = 1; column <= NUM_OF_LINES - row; column++)
                  System.out.print(" ");


              for (int num = 2; num <= row; num++)
                  System.out.print(num);



              System.out.println();
            }
    }else if((char)number == '3'){
          System.exit(0);
    }else {
            System.out.println("Enter 1 or 2 or 3to exit");
      }

  }
}
0
 
LVL 3

Expert Comment

by:CI-Ia0s
ID: 12197142
First question: Use an if statement.

Second question:

//Declare numDigits to be the number of digits you want
int wholeNumber = 0;
int digitHolder = 1;
for (int c = 1; c < numDigits; c++){

wholeNumber = wholeNumber + (c * digitHolder);
digitHolder = digitHolder * 10;
}
0
 

Author Comment

by:biloonline
ID: 12197194
<code>

import java.io.*;


public class Pattern4 {
  public static void main(String[] args) throws IOException {
    final int NUM_OF_LINES = 6;
    int number;
   
    BufferedReader stdin  = new BufferedReader (new InputStreamReader(System.in));
    System.out.println("Select Pattern 1 or 2 or 3 or 4 or 9 to exit the application");
   
    number = stdin.readLine();
 
   
    if (number == '1')
    {
 


                for (int row = 1; row <= NUM_OF_LINES; row++) {

            for (int num = 1; num <= row; num++)
              System.out.print(num);
      
         for (int column = 1; column <= NUM_OF_LINES - row; column++)
                 System.out.print(" ");


            System.out.println();
          }
    }
   
      if (number == '2')
      {
      
      
          for (int row = 1; row <= NUM_OF_LINES; row++) {

            for (int column = 1; column <= NUM_OF_LINES - row; column++)
              System.out.print(" ");


            for (int num = row; num >= 1; num--)
              System.out.print(num);



            System.out.println();
            }
    }

      if (number == '3')
      {
      
             for (int row = 1; row <= NUM_OF_LINES; row++) {

             for (int num = 1; num < row; num++)
               System.out.print(" ");

           for (int column = 1; column <= NUM_OF_LINES - row + 1; column++)
                System.out.print(column);
            
                System.out.print(" ");
                }
                
    if (number == '4')
       {
       
           for (int row = 1; row <= NUM_OF_LINES; row++) {

                    for (int num = 1; num < row; num++)
               System.out.print(" ");

            for (int column = 1; column <= NUM_OF_LINES - row + 1; column++)
            System.out.print(column);


             System.out.println();
             }
     }
  }
}
}


</code>

This is what I have gotten so far, I am getting 1 error
E:\Program Files\Xinox Software\JCreatorV3 LE\MyProjects\Hw3Pr1\Pattern4.java:12: incompatible types
found   : java.lang.String
required: int
    number = stdin.readLine();
                           ^
1 error

Process completed.

Please advise,
Thanks
0
 

Author Comment

by:biloonline
ID: 12197203
if (number == '1')  <-- I guess that would not be right, since in this case '1' is considered as a CHAR.

How do I convert from String to Char?

0
 

Author Comment

by:biloonline
ID: 12197213
Here is an updated version, It compiled with no errors, I will run it now ...

import java.io.*;


public class Pattern4 {
  public static void main(String[] args) throws IOException {
    final int NUM_OF_LINES = 6;
   
    BufferedReader stdin  = new BufferedReader (new InputStreamReader(System.in));
    System.out.println("Select Pattern 1 or 2 or 3 or 4 or 9 to exit the application");
   
    String number = stdin.readLine();
   
    int numb = Integer.parseInt(number);
 
   
    if (numb == 1)
    {
 


                for (int row = 1; row <= NUM_OF_LINES; row++) {

            for (int num = 1; num <= row; num++)
              System.out.print(num);
      
         for (int column = 1; column <= NUM_OF_LINES - row; column++)
                 System.out.print(" ");


            System.out.println();
          }
    }
   
      if (numb == 2)
      {
      
      
          for (int row = 1; row <= NUM_OF_LINES; row++) {

            for (int column = 1; column <= NUM_OF_LINES - row; column++)
              System.out.print(" ");


            for (int num = row; num >= 1; num--)
              System.out.print(num);



            System.out.println();
            }
    }

      if (numb == 3)
      {
      
             for (int row = 1; row <= NUM_OF_LINES; row++) {

             for (int num = 1; num < row; num++)
               System.out.print(" ");

           for (int column = 1; column <= NUM_OF_LINES - row + 1; column++)
                System.out.print(column);
            
                System.out.print(" ");
                }
                
    if (numb == 4)
       {
       
           for (int row = 1; row <= NUM_OF_LINES; row++) {

                    for (int num = 1; num < row; num++)
               System.out.print(" ");

            for (int column = 1; column <= NUM_OF_LINES - row + 1; column++)
            System.out.print(column);


             System.out.println();
             }
     }
  }
}
}
0
 

Author Comment

by:biloonline
ID: 12197216
and added this at the end:

       if (numb == 9)
             return;
             

Looks like it's working fine.

Thanks guys.
0
 
LVL 6

Expert Comment

by:expertmb
ID: 12197222
if (number == '1')
should be
if ((char)number == '1')
0
 

Author Comment

by:biloonline
ID: 12197227
But I am working with Int and not Char, the program compiles and works fine.
0
 
LVL 6

Expert Comment

by:expertmb
ID: 12197359
from api
read
public abstract int read()
                  throws IOExceptionReads the next byte of data from the input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.
A subclass must provide an implementation of this method.


0
 

Author Comment

by:biloonline
ID: 12197387
Thanks again.
0

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