From d40810fb5be6bfe41a5640b7a0b1f07097d6e788 Mon Sep 17 00:00:00 2001
From: Kraemerd <Dominic_Daniel.Kraemer@Student.Reutlingen-University.de>
Date: Tue, 10 Jan 2023 04:40:27 +0100
Subject: [PATCH] applied final changes to the project
---
expressions.txt | 14 +++---
src/main/ASTPrinter.java | 2 +-
src/main/Application.java | 11 +++++
src/main/Evaluator.java | 73 ++++++++++++++++++++++++++----
src/main/Parser.java | 1 +
src/main/SwingFunctionPlotter.java | 4 +-
src/test/EvaluatorTest.java | 52 +++++++++++++++++++--
7 files changed, 135 insertions(+), 22 deletions(-)
diff --git a/expressions.txt b/expressions.txt
index 7177c93..9f8b2ee 100644
--- a/expressions.txt
+++ b/expressions.txt
@@ -1,8 +1,6 @@
-1+1
-2*4+x
-2*5+2
-2+5*2
-2*(5+2)
-20*(5^2)
-(x^2)+50*x+2
-5*(2-5)+(4+2)+x
\ No newline at end of file
+x
+x^2
+(x^2)-40
+(x*40)-(x*20)
+(2*x)+(0.5*x^2)-1
+1 + (x^2) - (3*x)
\ No newline at end of file
diff --git a/src/main/ASTPrinter.java b/src/main/ASTPrinter.java
index 83ae465..4a16546 100644
--- a/src/main/ASTPrinter.java
+++ b/src/main/ASTPrinter.java
@@ -3,7 +3,7 @@ package main;
/**
* <h1>ASTPrinter</h1>
* The ASTPrinter class creates a String out of an AST(represented through an Expression object)
- * It prints it in a form the Evaluator & SwingFunctionPlotter class can work with it, it isn't primarily designed
+ * It prints it in a form the SwingFunctionPlotter class can work with it, it isn't primarily designed
* for returning a String that is perfect for human readability (e.g. Pow(x,3) would be printed instead of x^3)
*
* @version 1.0
diff --git a/src/main/Application.java b/src/main/Application.java
index 510bf3e..e180d50 100644
--- a/src/main/Application.java
+++ b/src/main/Application.java
@@ -68,6 +68,17 @@ public class Application {
ASTPrinter printer = new ASTPrinter();
System.out.println("Printing: '" + printer.visit(ast) + "'");
stringsForPlotter.add(printer.visit(ast));
+
+ //Prints the Value of the Expression
+ System.out.println("Evaluating:");
+ Evaluator eval = new Evaluator();
+ //Calculates the expression with values from -20 to 20
+ for(index=-20;index<=20; index++) {
+ System.out.print("[" + index + "]" + eval.visit(ast,index) + " ");
+ if(index%5==0 && index!=-20) {
+ System.out.println();
+ }
+ }
System.out.println("\n");
}
catch (Exception e) {
diff --git a/src/main/Evaluator.java b/src/main/Evaluator.java
index 9b1fb5e..bf534b9 100644
--- a/src/main/Evaluator.java
+++ b/src/main/Evaluator.java
@@ -2,19 +2,76 @@ package main;
/**
* <h1>Evaluator</h1>
- *
+ * This class calculates the value of an expression, using the visitor pattern.
+ * It visits every element of a given expression and combines them with the matching
+ * arithmetical operator.
* @version 1.0
* @since 09.01.2023
+ * @see #visit(Parser.Expression, int)
*/
-public class Evaluator {
+public class Evaluator implements Visitor<Double> {
- public double calculate(String expression, int variableValue) {
- int index = 0;
- while(index<expression.length())
- if(Character.isLetter(expression.charAt(index))) {
- expression.replaceAll(expression.substring(index, index+2),"XXX");
+ private double value;
+
+ @Override
+ public Double visit(final Parser.BinaryOperation expression) {
+ double result = expression.leftExpression.accept(this);
+ double rOperand = expression.rightExpression.accept(this);
+ switch (expression.operator) {
+ case "+":
+ result += rOperand;
+ break;
+ case "-":
+ result -= rOperand;
+ break;
+ case "*":
+ result *= rOperand;
+ break;
+ case "/":
+ if (rOperand!=0) {
+ result /= rOperand;
+ }
+ else {
+ throw new ArithmeticException("ArithmeticError: division by zero detected");
+ }
+ result /= rOperand;
+ break;
+ case "^":
+ for(double index=1.0; index<rOperand; index++) {
+ result *= result;
+ }
+ break;
+ default:
+ throw new RuntimeException("SemanticError: unknown operand found in AST: "
+ + expression.operator);
}
- return 0.0;
+ return result;
+ }
+
+ @Override
+ public Double visit(final Parser.Variable variable) {
+ return value;
}
+
+ @Override
+ public Double visit(final Parser.Decimal decimal) {
+ return Double.parseDouble(decimal.beforeDot.digits + "." + decimal.afterDot.digits);
+ }
+
+ @Override
+ public Double visit(final Parser.Number number) {
+ return Double.parseDouble(number.digits);
+ }
+
+ /**
+ * This method is used for visiting every element of an expression
+ * @param ast The expression in a form of an AST(Abstract Syntax Tree)
+ * @param value The int value which will be used for the variables
+ * @return The final value of the expression
+ */
+ public double visit(final Parser.Expression ast, int value) {
+ this.value = value;
+ return ast.accept(this);
+ }
}
diff --git a/src/main/Parser.java b/src/main/Parser.java
index 892bc36..8b44edd 100644
--- a/src/main/Parser.java
+++ b/src/main/Parser.java
@@ -206,6 +206,7 @@ public class Parser {
capsuled = false;
index = tokensInBracket+1;
}
+
//Checks if the operator of this BinaryOperation is permitted
parseOperator(ts.get(index).getData());
List<Lexer.Token> leftList = new LinkedList<>();
diff --git a/src/main/SwingFunctionPlotter.java b/src/main/SwingFunctionPlotter.java
index cd805de..63ec6b1 100644
--- a/src/main/SwingFunctionPlotter.java
+++ b/src/main/SwingFunctionPlotter.java
@@ -50,7 +50,7 @@ public class SwingFunctionPlotter extends JFrame {
//Keeps track of the current shown function
final int[] index = {0};
- getContentPane().add(initializeChart(function.get(0),2), BorderLayout.CENTER);
+ getContentPane().add(initializeChart(function.get(0),0), BorderLayout.CENTER);
//KeyListener that listens to every KeyInput of the user
addKeyListener(new KeyAdapter() {
@@ -97,7 +97,7 @@ public class SwingFunctionPlotter extends JFrame {
FunctionSeries series1;
try {
series1 = new FunctionSeries(function,1000, -20, 20);
- series1.setTitle("Function: " + function + "[" + index + "]");
+ series1.setTitle("Function " + (index+1) + ": " + function);
lineChart.getSeries().add(series1);
}
catch(Exception e) {
diff --git a/src/test/EvaluatorTest.java b/src/test/EvaluatorTest.java
index 8379942..c88f48a 100644
--- a/src/test/EvaluatorTest.java
+++ b/src/test/EvaluatorTest.java
@@ -1,13 +1,59 @@
package test;
import main.Evaluator;
-import org.junit.Test;
+import main.Lexer;
+import main.Parser;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
public class EvaluatorTest {
@Test
- public void testFirstExpression() {
- var Evaluator = new Evaluator();
+ public void testWithString1() {
+ String s = "1 + (x^2) - (3*x)";
+ var parser = new Parser();
+ var evaluator = new Evaluator();
+ try {
+ var tokens = Lexer.lex(s);
+ var ast = parser.parse(tokens);
+ var value = evaluator.visit(ast, 5);
+ assertEquals(value,11);
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
+ }
+
+ @Test
+ public void testWithString2() {
+ String s = "(2*x)+(0.5*x^2)-1";
+ var parser = new Parser();
+ var evaluator = new Evaluator();
+ try {
+ var tokens = Lexer.lex(s);
+ var ast = parser.parse(tokens);
+ var value = evaluator.visit(ast, 8);
+ assertEquals(value,47);
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
+ }
+ @Test
+ public void testWithString3() {
+ String s = "(x^2)-40";
+ var parser = new Parser();
+ var evaluator = new Evaluator();
+ try {
+ var tokens = Lexer.lex(s);
+ var ast = parser.parse(tokens);
+ var value = evaluator.visit(ast, 4);
+ assertEquals(value,-24);
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
}
}
--
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