MathBackend: Introduced usesZeroBasedIndexing to define indexing type

src/main/java/de/monticore/lang/monticar/generator/MathBackend.java

@@ -37,4 +37,11 @@ public interface MathBackend {
 
     String getDivisionEEString(MathMatrixArithmeticExpressionSymbol mathExpressionSymbol, String valueListString);
 
+    /**
+     * Does the backend use 0-based or 1-based indexing for matrix element access?
+     *
+     * @return whether the backend uses zero based indexing (true) or one based indexing (false)
+     */
+    boolean usesZeroBasedIndexing();
+
 }

src/main/java/de/monticore/lang/monticar/generator/cpp/ArmadilloBackend.java

@@ -101,4 +101,9 @@ public class ArmadilloBackend implements MathBackend {
         return ExecuteMethodGenerator.generateExecuteCode(mathExpressionSymbol.getLeftExpression(), new ArrayList<>()) + "/" +
                 ExecuteMethodGenerator.generateExecuteCode(mathExpressionSymbol.getRightExpression(), new ArrayList<>());
     }
+
+    @Override
+    public boolean usesZeroBasedIndexing() {
+        return true;
+    }
 }

src/main/java/de/monticore/lang/monticar/generator/cpp/LinalgBackend.java

@@ -88,4 +88,10 @@ public class LinalgBackend implements MathBackend {
         Log.error("Not supported yet");
         return null;
     }
+
+    @Override
+    public boolean usesZeroBasedIndexing() {
+        // TODO: check this! Do not know this backend...
+        return false;
+    }
 }

src/main/java/de/monticore/lang/monticar/generator/cpp/OctaveBackend.java

@@ -92,5 +92,8 @@ public class OctaveBackend implements MathBackend {
         return OctaveHelper.getCallOctaveFunctionFirstResult(mathExpressionSymbol.getLeftExpression(), "ldivide", valueListString, false);
     }
 
-
+    @Override
+    public boolean usesZeroBasedIndexing() {
+        return false;
+    }
 }