Please Help

Question about the task

Problem solving

Java Core, Level 9, Lesson 8

Under discussion

Where is The Error

Replace the main method's System.outx object with your own reader wrapper similar to the one shown in the lesson.
Your reader wrapper should output the solution to the console.
Call testString's existing printSomething() method.
Restore the System.out variable back to the original stream.

Possible operations: + - *
Format of input and output: a [operator] b = c
Negative numbers, fractions, and unary operators (such as factorials and square roots) are not allowed.

Example output:
3 + 6 = 9

Requirements:

The Solution class must contain a TestString class.
The Solution class must have a public static TestString field called testString that is initialized immediately.
The TestString class must have a public void printSomething() method.
The TestString class's printSomething() method must display the string "3 + 6 = ".
The Solution class's main(String[] args) method must create a PrintStream object (use the PrintStream constructor with a ByteArrayOutputStream parameter).
The Solution class's main(String[] args) method should replace and then restore the console output stream (System.out).
The Solution class's main(String[] args) method must call testString's printSomething() method.
The Solution class's main(String[] args) method must modify the line printed by the printSomething() method, as per the task conditions, and output it to the console.

package com.codegym.task.task19.task1914; /* Problem solving */ import java.io.ByteArrayOutputStream; import java.io.PrintStream; import java.util.ArrayList; public class Solution { public static TestString testString = new TestString(); public static void main(String[] args) { PrintStream consoleStream = System.out; ByteArrayOutputStream outputStream = new ByteArrayOutputStream(); PrintStream stream = new PrintStream(outputStream); System.setOut(stream); testString.printSomething(); //This line will print to the ByteArrayOutputStream and not the console. System.setOut(consoleStream); //Restore the original consoleStream. //Remove all spaces from the streamResult string. String streamResult = outputStream.toString(); ArrayList<String> digitString = new ArrayList<>(); //Get all the numbers from the streamResult (outputstream) while (true) { if (streamResult.length() == 0) break; digitString.add(streamResult.substring(0, streamResult.indexOf(" "))); streamResult = streamResult.substring(streamResult.indexOf(" ") + 3); } //Get all the operators and store in the operators string String operators = ""; for (int i : outputStream.toByteArray()) { if (i == 42 || i == 43 || i == 45) operators += (char) i; } //Get the first number from the digitString list double finalResult = Double.parseDouble(digitString.get(0)); //Perform the operation with the finalResult and the next number. //The next number is always at index i+1 for (int i = 0; i < operators.length(); i++) { if ("-".equals(String.valueOf(operators.charAt(i)))) finalResult -= Double.parseDouble(digitString.get(i+1)); if ("*".equals(String.valueOf(operators.charAt(i)))) finalResult *= Double.parseDouble(digitString.get(i+1)); if ("+".equals(String.valueOf(operators.charAt(i)))) finalResult += Double.parseDouble(digitString.get(i+1)); } //Now print out the result of the operation and round up finalResult System.out.println(outputStream.toString() + Math.round(finalResult)); } public static class TestString { public void printSomething() { System.out.print("3 + 6 = "); } } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

14 November 2019, 19:14