Meet the output, but last condition fail

Question about the task

Problem solving

Java Core, Level 9, Lesson 8

Under discussion

I tested code and meet goal, but cant pass the last condition. please help.

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.Arrays; public class Solution { public static TestString testString = new TestString(); public static void main(String[] args) { PrintStream out = System.out; ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(); PrintStream ps = new PrintStream(byteArrayOutputStream); System.setOut(ps); testString.printSomething(); System.setOut(out); String[] str = byteArrayOutputStream.toString().split(" "); System.out.println(str.length); String s =""; switch (str[1]){ case "+": int a = Integer.parseInt(str[0]); int b = Integer.parseInt(str[2]); int c = a + b; str[4] = String.valueOf(c); break; case "-": int a1 = Integer.parseInt(str[0]); int b1 = Integer.parseInt(str[2]); int c1 = a1 - b1; str[4] = String.valueOf(c1); break; case "*": int a2 = Integer.parseInt(str[0]); int b2 = Integer.parseInt(str[2]); int c2 = a2 * b2; str[4] = String.valueOf(c2); break; } s = Arrays.toString(str).replaceAll(",", ""); System.out.println(s); } public static class TestString { public void printSomething() { System.out.println("3 + 6 = "); } } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

6 November 2019, 19:44

Have you tried removing line 24? also i don't think the output answer should be contained in brackets. You can fix this easy enough by using this regex in the replaceAll method: "[\\[\\],]"

Guadalupe Gagnon

Level 37 , Tampa, United States

6 November 2019, 19:55

A tip too. Whenever you are duplicating lines of code multiple times, you can extract that code and reduce your lines. Lines 27-51 can be rewritten to:

int a = Integer.parseInt(str[0]);
int b = Integer.parseInt(str[2]);
int c = 0;
switch (str[1]){
   case "+":
      c = a + b;
      break;
   case "-":
      c = a - b;
      break;
   case "*":
      c = a * b;
      break;
}
str[4] = String.valueOf(c);

and have the same functionality. This also becomes very handy if you want to debug your code.