Question

I’m working on a Bruce Eckel exercise on how to take a keyboard command line input and put it into an array. It’s supposed to take 3 separate inputs and place them into an array and print them back out.

Here is the code I have so far:

//: object/PushtoArray import java.io.*; import java.util.*;  class PushtoArray {      public static void main(String[] args) {      String[] s = new String[3];      int i = 0;       //initialize console      Console c = System.console();         while ( i <= 2 ) {         //prompt entry:         //System.out.println('Enter entry #' + i + ': ');           //readin              s[i] = c.readLine('enter entry #' + i + ': ');           //increment counter          i++;                      } //end while       //reset counter      i = 0;       //print out array     while ( i <= 2 ) {          System.out.println(s[i]);             i++;     } //end while      }//end main  } //end class 

UPDATE: Now I get a different error:

PushtoArray.java:15: readline(boolean) in java.io.Console cannot be applied to (java.lang.string)        s[i]= c.readline('Enter entry #' + i + ': '); 

I’m trying to read in from the command prompt but it isn’t prompting at all. It compiles correctly when I javac the java file.

Am I using the wrong function? Should I be using a push method instead of an assignment?

Answer 1

Are you sure you’re running javac on the right file? There is no way that file could compile.

1. You need a semicolon on the import statement:

   import java.io.*; 

2. You forgot an end brace:

   } // end main() 

3. There is no such method as readline(). You need to read from System.in. The easiest way is to make a Scanner before the loop, then read from it in the loop. See the Javadocs for Scanner for an example.

Edit: See the Java Tutorials for more on reading from the command line. The Console class (introduced in Java 6) looks like it has the readLine() method that you wanted.

Edit 2: You need to capitalize Line. You wrote ‘readline‘, but it should be ‘readLine‘.