Added integer underflow

wk2/Java/negative.bb

+clear x;
+decr x;
\ No newline at end of file

wk2/Java/src/jrr1g18/bb/Interpreter.java

@@ -4,8 +4,10 @@ import java.io.BufferedReader;
 import java.io.FileNotFoundException;
 import java.io.FileReader;
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Objects;
@@ -13,13 +15,14 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 public class Interpreter {
-
     private Map<String, Integer> m_vars = new HashMap<>();
-    private Map<Integer, String> m_code = new HashMap<>();
-    private Map<Integer, Integer> whiles = new HashMap<>();
+    private List<String> m_code = new ArrayList<>();
+    private Map<Integer, Integer> m_whiles = new HashMap<>();
     private int m_lineCount = 0;
     private int m_whileDepth = 0;
 
+    private final String m_filename;
+
     private static final Map<InstructionType, String> INSTRUCTION_NAMES;
 
     static {
@@ -36,7 +39,7 @@ public class Interpreter {
 	INCR, DECR, CLEAR, WHILE, END,
     }
 
-    private InstructionType stringToInstructionType(String instruction) {
+    private static InstructionType stringToInstructionType(String instruction) {
 	for(Entry<InstructionType, String> entry : INSTRUCTION_NAMES
 		.entrySet()) {
 	    if(Objects.equals(instruction, entry.getValue())) {
@@ -56,8 +59,14 @@ public class Interpreter {
 	return stripWhitespace(m.group(1));
     }
 
-    public void run(String fileName) {
-	readCode(fileName);
+    public Interpreter(String fileName) {
+	m_filename = fileName;
+    }
+
+    public void run() {
+	readCode();
+	validateCode();
+	exec();
     }
 
     public String variablesToString() {
@@ -147,12 +156,12 @@ public class Interpreter {
 	}
     }
 
-    private void readCode(String nameOfTheFile) {
-	try(BufferedReader br =
-		new BufferedReader(new FileReader(nameOfTheFile))) {
+    private void readCode() {
+	try(BufferedReader reader =
+		new BufferedReader(new FileReader(m_filename))) {
 	    String line;
-	    while((line = br.readLine()) != null) {
-		m_code.put(m_lineCount, line);
+	    while((line = reader.readLine()) != null) {
+		m_code.add(line);
 		m_lineCount++;
 	    }
 	} catch(FileNotFoundException e) {
@@ -160,9 +169,6 @@ public class Interpreter {
 	} catch(IOException e) {
 	    e.printStackTrace();
 	}
-
-	validateCode();
-	exec();
     }
 
     private void exec() {
@@ -210,9 +216,10 @@ public class Interpreter {
 	    System.err.println("Error: Variable " + name + " doesn't exist");
 	    System.exit(1);
 	} else if(m_vars.get(name) == 0) {
-	    System.err
-		    .println("Error: Variable " + name + " cannot be negative");
-	    System.exit(1);
+//	    System.err
+//		    .println("Error: Variable " + name + " cannot be negative");
+//	    System.exit(1);
+	    m_vars.put(name, Integer.MAX_VALUE);
 	} else {
 	    m_vars.put(name, m_vars.get(name) - 1);
 	}
@@ -226,7 +233,7 @@ public class Interpreter {
 	String line;
 	if(splitLine[0].equals("while")) {
 	    m_whileDepth++;
-	    whiles.put(m_whileDepth, idx);
+	    m_whiles.put(m_whileDepth, idx);
 
 	    int condition = Integer.parseInt(splitLine[3]);
 	    if(isVariableNull(splitLine[1])
@@ -238,12 +245,12 @@ public class Interpreter {
 		}
 	    }
 	} else {
-	    line = m_code.get(whiles.get(m_whileDepth));
+	    line = m_code.get(m_whiles.get(m_whileDepth));
 	    splitLine = splitLine(line);
 	    int condition = Integer.parseInt(splitLine[3]);
 
 	    if(m_vars.get(splitLine[1]) != condition)
-		idx = whiles.get(m_whileDepth);
+		idx = m_whiles.get(m_whileDepth);
 	    else {
 		m_whileDepth--;
 	    }

wk2/Java/src/jrr1g18/bb/Main.java

@@ -3,8 +3,8 @@ package jrr1g18.bb;
 public class Main {
 
     public static void main(String[] args) {
-	Interpreter interpreter = new Interpreter();
-	interpreter.run("multiply.bb");
+	Interpreter interpreter = new Interpreter("negative.bb");
+	interpreter.run();
 	System.out.println(interpreter.variablesToString());
     }