Member Avatar for mikki2

hi, i'm new to java (being studying for a few days now) and i'm stuck on the following program. it's supposed to bring up a screen and ask me to input a number...but it always say there's something wrong with the line userInput = TextIO.getInt(); . can anyone help me out...thanks

here it is;

public class PrintSquare {

                  public static void main(String[] args) {

                     // A program that computes and prints the square
                     // of a number input by the user.

                     int userInput;  // the number input by the user
                     int square;     // the userInput, multiplied by itself
                     
                     System.out.print("Please type a number: ");
                     userInput = TextIO.getInt();
                     square = userInput * userInput;
                     System.out.print("The square of that number is ");
                     System.out.println(square);
                     
                  } // end of main()
                  
                } //end of class PrintSquare
  • 4 Contributors
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  • Latest Post Latest Post by iwlu

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Generated

Short note tying the replies together and giving a safe, practical fix.

As pointed out, TextIO is not part of the standard JDK; it is a helper class used in some textbooks (and later located a copy). ’s suggestion to use Scanner is a fine standard alternative. ’s BufferedReader idea is also valid, but reader.read() reads a single character code (not a full line), which will produce wrong results for multi-digit numbers.

A concise, robust BufferedReader pattern (reads a whole line and parses it, with error handling):

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

public class PrintSquare {
  public static void main(String[] args) {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    try {
      System.out.print("Please type a number: ");
      String line = br.readLine();
      int n = Integer.parseInt(line.trim());
      System.out.println("The square of that number is " + (n * n));
    } catch (IOException | NumberFormatException e) {
      System.err.println("Invalid input");
    }
  }
}

Troubleshooting notes when using a helper class like TextIO: compile the helper and the program together (or put the helper on the classpath), and ensure package declarations match—classes in different packages require proper package/import usage. From the command line, javac TextIO.java PrintSquare.java then java PrintSquare.

Reference documentation: Scanner and BufferedReader API docs are useful for input details (Scanner, BufferedReader). A final caution: java.io.Console can return null when running inside some IDEs, so prefer Scanner or BufferedReader there.

Recommended Answers

All 5 Replies

Member Avatar for jwenting

You're missing a class "TextIO" and the import statement for it.

Member Avatar for mikki2

thanks for the reply. i read in the appendix of the book i'm using about adding TextIO, but it doesnt say where i should add it. can you (or anyone) explain what i'm supposed to do step by step.

thanks for your patience

Member Avatar for aripaka

Hi,
i can sugggest that for reading use input from console u may try using BufferedReader from java.io. Like the one below:

public class PrintSquare {

                  public static void main(String[] args) {

                     // A program that computes and prints the square
                     // of a number input by the user.

                     int userInput=0;  // the number input by the user
                     int square;     // the userInput, multiplied by itself
                     BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

                     System.out.print("Please type a number: ");
                     //userInput = TextIO.getInt();
                     try{
                     userInput=reader.read();
             		}catch(IOException e){};
                     square = userInput * userInput;
                     System.out.print("The square of that number is ");
                     System.out.println(square);
                     
                  } // end of main()
                  
                } //end of class PrintSquare

Please correct me if i am wrong. Suggestions abt other alternatives are most welcome.

Member Avatar for mikki2

i've figured it out. i found a site where i can copy the missing TextIO class. i saved it in the same folder as all my java programs.

here's the site incase anyone needs it


Thanks for the help

Member Avatar for iwlu

hi, i'm new to java (being studying for a few days now) and i'm stuck on the following program. it's supposed to bring up a screen and ask me to input a number...but it always say there's something wrong with the line userInput = TextIO.getInt(); . can anyone help me out...thanks

here it is;

public class PrintSquare {
 
                  public static void main(String[] args) {
 
                     // A program that computes and prints the square
                     // of a number input by the user.
 
                     int userInput;  // the number input by the user
                     int square;     // the userInput, multiplied by itself
 
                     System.out.print("Please type a number: ");
                     userInput = TextIO.getInt();
                     square = userInput * userInput;
                     System.out.print("The square of that number is ");
                     System.out.println(square);
 
                  } // end of main()
 
                } //end of class PrintSquare

Here is what your looking for:
Highlighted show's your missing information.

import java.util.Scanner;
public class PrintSquare {
                  public static void main(String[] args) {
// creates scanner to obtain input from command window
    Scanner input = new Scanner(System.in); 
                     // A program that computes and prints the square
                     // of a number input by the user.
                     int userInput;  // the number input by the user
                     int square;     // the userInput, multiplied by itself
                     
                     System.out.print("Please type a number: ");
                     userInput = input.nextInt();
                     square = userInput * userInput;
                     System.out.print("The square of that number is ");
                     System.out.println(square);
                     
                  } // end of main()
                  
                } //end of class PrintSquare
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