Improve Derivatiles: bug fixes, new gameplay features, and code cleanup

functions.txt

@@ -1,6 +1,6 @@
-x + sin(x) 
+x + sin(x)
 2x^2 + 9x
-3x^7 - cos(x) 
+3x^7 - cos(x)
 2x^3 - 9
 4x^2 + 6
 3x^5 - 21
@@ -25,4 +25,26 @@ x^2 + 2x - 1
 9x^4 - 8x
 42x^5 + cos(x)
 5x^3 + sin(x)
-56x^3 - cos(x)
+56x^3 - cos(x)
+8x^3 + 3x^2 - 7x
+12x^2 + 5x + 3
+6x^5 - 4x^3
+7x^4 + 2x^2 - 10
+15x^3 + sin(x)
+20x^2 - 7x + 4
+x^3 + x^2 + x
+11x^2 - cos(x)
+4x^6 - 3x
+2x^5 + 8x^3 - 1
+9x^3 + 14x
+33x^2 + sin(x)
+x^4 - 6x^2 + 9
+7x^3 - 5x + 2
+18x^4 + cos(x)
+50x^3 - 25x
+6x^2 + 12x - 8
+x^5 - sin(x)
+14x^3 + 7x^2
+8x^4 - cos(x)
+3x^6 + 2x
+100x^2 - 50x + 1

src/BoardState.java

@@ -60,7 +60,7 @@ public static String[][] getGrid(String f, int numDerivs, int numOptions) {
                     continue;
                 }
 
-                if (correctDerivative == "0") {
+                if (correctDerivative.equals("0")) {
                     tempChoices.add(Integer.toString((int) (Math.random() * 9) + 1));
                     continue;
                 }
@@ -78,7 +78,6 @@ public static String[][] getGrid(String f, int numDerivs, int numOptions) {
 
             }
 
-            System.out.println("this is temp choices:" + tempChoices);
 
             List<String> choicesShuffle = new ArrayList<String>(tempChoices);
             Collections.shuffle(choicesShuffle);

src/Differentiate.java

@@ -1,7 +1,6 @@
 package src;
 
 import java.util.*;
-import javax.swing.tree.TreeModel;
 
 /**
  * Performs differentiating calculations.
@@ -38,31 +37,27 @@ public String differentiateString(String function) {
 
         // "3x^2 + cos(x)" => ["3x^2", "+", "cos(x)"]
         // "3x^2 - cos(x)" => ["3x^2", "-", "cos(x)"]
-        String[] terms = function.split(" ");
+        String[] terms = function.trim().split(" ");
         String answer = "";
-        boolean uselessAndOnlyForConstAtBeginningCase = false;
+        boolean skipNextSign = false;
         for (int i = 0; i < terms.length; i++) {
 
             String termOrSign = terms[i];
 
-            System.out.println("this is termor sign: " + terms[i]);
-
             // CORNER CASE: ONLY A CONSTANT
             if (terms.length == 1 && terms[i].indexOf("x") < 0) {
-                System.out.println("this is terms[i]: " + terms[i]);
                 answer = "0";
                 break;
             }
 
-            else if (uselessAndOnlyForConstAtBeginningCase) {
-                uselessAndOnlyForConstAtBeginningCase = false;
+            else if (skipNextSign) {
+                skipNextSign = false;
                 if ((termOrSign.equals("+") || termOrSign.equals("-"))) {
                     answer += termOrSign + " ";
                 }
                 continue;
             }
 
-            System.out.println("this is termor sign: " + termOrSign);
             if (!(termOrSign.equals("+") || termOrSign.equals("-"))) {
                 if (termOrSign.equals("x") && termOrSign.length() == 1) {
                     answer += "1 ";
@@ -73,7 +68,7 @@ else if (uselessAndOnlyForConstAtBeginningCase) {
                 if (!termOrSign.contains("x")) {
                     // 4 + x
                     if (answer.length() == 0) {
-                        uselessAndOnlyForConstAtBeginningCase = true;
+                        skipNextSign = true;
                     }
                     // x + 4 of x + 4 + x
                     else if (answer.length() > 0) {
@@ -103,12 +98,18 @@ else if (answer.length() > 0) {
                     }
 
                     int derivCoefficient = 1;
-                    if (!derivativeTerm.substring(0, 1).equals("x")) {
-                        derivCoefficient = Integer.parseInt(derivativeTerm.substring(0, 1));
+                    // Parse multi-digit derivative coefficients
+                    int derivCoeffEnd = 0;
+                    while (derivCoeffEnd < derivativeTerm.length()
+                            && Character.isDigit(derivativeTerm.charAt(derivCoeffEnd))) {
+                        derivCoeffEnd++;
+                    }
+                    if (derivCoeffEnd > 0) {
+                        derivCoefficient = Integer.parseInt(derivativeTerm.substring(0, derivCoeffEnd));
                     }
 
                     String finalCoefficient = (derivCoefficient * preCoefficient) + "";
-                    String finalExpression = finalCoefficient + derivativeTerm.substring(1);
+                    String finalExpression = finalCoefficient + derivativeTerm.substring(derivCoeffEnd);
                     answer += finalExpression + " ";
                 }
 
@@ -216,7 +217,6 @@ public String[] correctAnswers(String function, int numOrders) {
     public static void main(String[] args) {
         Differentiate diff = new Differentiate();
         System.out.println(diff.differentiateString("15120 - sin(x)"));
-        System.out.println("damn memer omment".hashCode());
     }
 
 }