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POPostfix Evaluation using Stacks
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copied!<p>I'm trying to write a method that solves a postfix equation. For ex. </p> <pre><code>1 2 + 3 * </code></pre> <p>This would = <code>9</code></p> <p>As of now I'm getting a <code>ArrayoutofboundsException</code>. I think the problem is around my <code>if(statement)</code> in my <code>postFixEvaluation</code> Method.</p> <p>The first part of code is the method I was talking about where I need the help. After that is the rest of my code. Not sure if yall need to read that or not. </p> <pre><code>public int PostfixEvaluate(String e) { String Operator = ""; int number1; int number2; int result = 0; char c; number1 = 0; number2 = 0; for (int j = 0; j < e.length(); j++) { c = e.charAt(j); if (c == (Integer) (number1)) { s.push(c); } else { number1 = s.pop(); number2 = s.pop(); switch (c) { case '+': result = number1 + number2; break; case '-': result = number1 - number2; break; case '*': result = number1 * number2; break; case '/': result = number1 / number2; break; case '%': result = number1 % number2; break; } } } return result; } public static void main(String[] args) { Stacked st = new Stacked(100); String y = new String("(z * j)/(b * 8) ^2"); String x = new String("10 3 + 9 *"); TestingClass clas = new TestingClass(st); clas.test(y); //System.out.println(stacks.test(y)); clas.PostfixEvaluate(x); } </code></pre> <hr> <p>Here's the rest of code that may be relevant: </p> <pre><code>public class Stacked { int top; char stack[]; int maxLen; public Stacked(int max) { top = 0; maxLen = max; stack = new char[maxLen]; } public void push(int result) { top++; stack[top] = (char) result; } public int pop() { int x; x = stack[top]; //top = top - 1; top--; return x; } public boolean isStackEmpty() { if (top == 0) { System.out.println("Stack is empty " + "Equation Good"); return true; } else System.out.println("Equation is No good"); return false; } public void reset() { top = -1; } public void showStack() { System.out.println(" "); System.out.println("Stack Contents..."); for (int j = top; j > -1; j--) { System.out.println(stack[j]); } System.out.println(" "); } public void showStack0toTop() { System.out.println(" "); System.out.println("Stack Contents..."); for (int j = 0; j >= top; j++) { System.out.println(stack[j]); } System.out.println(" "); } } </code></pre>

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