Thread: Cannot Find Variable/Symbol Errors... why?

Hello bgroenks96.

This is a simple error.

You get this because you are attempting to call these variables which are defined within the try/catch. They are unreachable.

To demonstrate this, you can see how the error stops when you remove the try/catch blocks.

public class Algebra {
	public void linearAlg() {
 
		System.out.println("Enter variables a b and c in ax+b=c");
 
			CalcInput user = new CalcInput();
			String userInput = user.getUserInput(" ");
			double a = Double.parseDouble(userInput);
			String userInput2 = user.getUserInput(" ");
			double b = Double.parseDouble(userInput2);
			String userInput3 = user.getUserInput(" ");
			double c = Double.parseDouble(userInput3);
 
		if (b < 0) {
			AlgebraHelper helper = new AlgebraHelper();
			helper.setVars(b, c);
			double addNum = helper.addThis();
			helper.setVars(addNum, c);
			double divNum = helper.divThis();
			System.out.println(divNum);
		} else if (b == 0) {
			AlgebraHelper helper = new AlgebraHelper();
			helper.setVars(a, c);
			double divNum = helper.divThis();
			System.out.println(divNum);
		} else {
			AlgebraHelper helper = new AlgebraHelper();
			helper.setVars(b, c);
			double subNum = helper.subThis();
			helper.setVars(subNum, c);
			double divNum = helper.divThis();
			System.out.println(divNum);
		}
	}
}

To fix, just place the if statements within the try/catch like so:

public class Algebra {
  public void linearAlg() {
    System.out.println("Enter variables a b and c in ax+b=c");
    try {
      CalcInput user = new CalcInput();
      String userInput = user.getUserInput(" ");
      double a = Double.parseDouble(userInput);
      String userInput2 = user.getUserInput(" ");
      double b = Double.parseDouble(userInput2);
      String userInput3 = user.getUserInput(" ");
      double c = Double.parseDouble(userInput3);
 
 
      if(b < 0) {
          AlgebraHelper helper = new AlgebraHelper();
          helper.setVars(b,c);
          double addNum = helper.addThis();
          helper.setVars(addNum,c);
          double divNum = helper.divThis();
          System.out.println(divNum);
        } else if(b == 0) {
          AlgebraHelper helper = new AlgebraHelper();
          helper.setVars(a,c);
          double divNum = helper.divThis();
          System.out.println(divNum);
        } else {
          AlgebraHelper helper = new AlgebraHelper();
          helper.setVars(b,c);
          double subNum = helper.subThis();
          helper.setVars(subNum,c);
          double divNum = helper.divThis();
          System.out.println(divNum);
        }
 
 
    } catch(NumberFormatException e) {
      System.out.println("Your input was invalid.  Only numeric real entries are accepted.");
      System.out.println("Do not use operators.  Enter the a,b and c variables in ax+b=c");
      System.out.println("");
    } catch(NullPointerException e) {
      System.out.println("There must be an input!");
      System.out.println("");
    }
 
  }
}

Originally Posted by Junky

All of which was explained in my explanation in the post I linked to. But I guess it was too hard for you to follow that link and read what I said. No thanks for me and no more help for you!

Indeed all of this was in the link provided. I just felt like expanding on your answer.
Your contributions are appreshiated as always Junky!