diff --git a/build/ast.o b/build/ast.o
index c17c079..64be2af 100644
Binary files a/build/ast.o and b/build/ast.o differ
diff --git a/build/ast_printer.o b/build/ast_printer.o
index 4181c35..d464cb0 100644
Binary files a/build/ast_printer.o and b/build/ast_printer.o differ
diff --git a/build/codegen.o b/build/codegen.o
index 1f3e5a5..324067e 100644
Binary files a/build/codegen.o and b/build/codegen.o differ
diff --git a/build/lexer.o b/build/lexer.o
index 0569422..3d34873 100644
Binary files a/build/lexer.o and b/build/lexer.o differ
diff --git a/build/parser.o b/build/parser.o
index c4bde76..5ee9ebc 100644
Binary files a/build/parser.o and b/build/parser.o differ
diff --git a/src/ast.cpp b/src/ast.cpp
index 2d6cfaf..79944f4 100644
--- a/src/ast.cpp
+++ b/src/ast.cpp
@@ -11,6 +11,7 @@ void SetPropExpr::accept(ASTVisitor& visitor) { visitor.visit(*this); }
 void ArrayExpr::accept(ASTVisitor& visitor) { visitor.visit(*this); }
 void IndexExpr::accept(ASTVisitor& visitor) { visitor.visit(*this); }
 void ArrayAssignExpr::accept(ASTVisitor& visitor) { visitor.visit(*this); }
+void IncrementExpr::accept(ASTVisitor& visitor) { visitor.visit(*this); }
 void BinaryExpr::accept(ASTVisitor& visitor) { visitor.visit(*this); }
 void ReturnStmt::accept(ASTVisitor& visitor) { visitor.visit(*this); }
 void VarDeclStmt::accept(ASTVisitor& visitor) { visitor.visit(*this); }
diff --git a/src/ast.h b/src/ast.h
index be613dd..68f61c6 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -108,6 +108,13 @@ public:
     void accept(ASTVisitor& visitor) override;
 };
 
+class IncrementExpr : public Expr {
+public:
+    std::unique_ptr<Expr> variable; // Can be VariableExpr, GetPropExpr, IndexExpr
+    IncrementExpr(std::unique_ptr<Expr> variable) : variable(std::move(variable)) {}
+    void accept(ASTVisitor& visitor) override;
+};
+
 class BinaryExpr : public Expr {
 public:
     std::unique_ptr<Expr> left;
@@ -239,6 +246,7 @@ public:
     virtual void visit(ArrayExpr& node) = 0;
     virtual void visit(IndexExpr& node) = 0;
     virtual void visit(ArrayAssignExpr& node) = 0;
+    virtual void visit(IncrementExpr& node) = 0;
     virtual void visit(BinaryExpr& node) = 0;
     virtual void visit(ReturnStmt& node) = 0;
     virtual void visit(VarDeclStmt& node) = 0;
diff --git a/src/ast_printer.cpp b/src/ast_printer.cpp
index ecf8842..18524a4 100644
--- a/src/ast_printer.cpp
+++ b/src/ast_printer.cpp
@@ -130,3 +130,60 @@ void ASTPrinter::visit(ClassDef& node) {
     }
     std::cout << "}";
 }
+
+void ASTPrinter::visit(ArrayExpr& node) {
+    std::cout << "[";
+    for (size_t i = 0; i < node.elements.size(); ++i) {
+        node.elements[i]->accept(*this);
+        if (i < node.elements.size() - 1) std::cout << ", ";
+    }
+    std::cout << "]";
+}
+
+void ASTPrinter::visit(IndexExpr& node) {
+    node.array->accept(*this);
+    std::cout << "[";
+    node.index->accept(*this);
+    std::cout << "]";
+}
+
+void ASTPrinter::visit(ArrayAssignExpr& node) {
+    node.array->accept(*this);
+    std::cout << "[";
+    node.index->accept(*this);
+    std::cout << "] = ";
+    node.value->accept(*this);
+}
+
+void ASTPrinter::visit(IncrementExpr& node) {
+    node.variable->accept(*this);
+    std::cout << "++";
+}
+
+void ASTPrinter::visit(ForInStmt& node) {
+    std::cout << "for (var " << node.variableName << " in ";
+    node.collection->accept(*this);
+    std::cout << ") ";
+    node.body->accept(*this);
+}
+
+void ASTPrinter::visit(SwitchStmt& node) {
+    std::cout << "switch (";
+    node.condition->accept(*this);
+    std::cout << ") {" << std::endl;
+    for (const auto& c : node.cases) {
+        std::cout << "case ";
+        c.value->accept(*this);
+        std::cout << ": ";
+        c.body->accept(*this);
+    }
+    if (node.defaultCase) {
+        std::cout << "default: ";
+        node.defaultCase->accept(*this);
+    }
+    std::cout << "}";
+}
+
+void ASTPrinter::visit(BreakStmt& node) {
+    std::cout << "break;";
+}
diff --git a/src/ast_printer.h b/src/ast_printer.h
index 90f861f..048697f 100644
--- a/src/ast_printer.h
+++ b/src/ast_printer.h
@@ -16,6 +16,10 @@ public:
     void visit(NewExpr& node) override;
     void visit(GetPropExpr& node) override;
     void visit(SetPropExpr& node) override;
+    void visit(ArrayExpr& node) override;
+    void visit(IndexExpr& node) override;
+    void visit(ArrayAssignExpr& node) override;
+    void visit(IncrementExpr& node) override;
     void visit(BinaryExpr& node) override;
     void visit(ReturnStmt& node) override;
     void visit(VarDeclStmt& node) override;
@@ -23,6 +27,9 @@ public:
     void visit(IfStmt& node) override;
     void visit(WhileStmt& node) override;
     void visit(ForStmt& node) override;
+    void visit(ForInStmt& node) override;
+    void visit(SwitchStmt& node) override;
+    void visit(BreakStmt& node) override;
     void visit(ExpressionStmt& node) override;
     void visit(FunctionDef& node) override;
     void visit(ClassDef& node) override;
diff --git a/src/codegen.cpp b/src/codegen.cpp
index 2a85935..9b4726a 100644
--- a/src/codegen.cpp
+++ b/src/codegen.cpp
@@ -248,6 +248,87 @@ void CodeGen::visit(CallExpr& node) {
     lastClassName = "";
 }
 
+void CodeGen::visit(IncrementExpr& node) {
+    if (auto varExpr = dynamic_cast<VariableExpr*>(node.variable.get())) {
+        if (namedValues.find(varExpr->name) == namedValues.end()) {
+            std::cerr << "Unknown variable: " << varExpr->name << std::endl;
+            lastValue = nullptr;
+            return;
+        }
+        llvm::AllocaInst* alloca = namedValues[varExpr->name];
+        llvm::Value* val = builder->CreateLoad(alloca->getAllocatedType(), alloca, varExpr->name.c_str());
+        lastValue = val; // Return old value
+        
+        llvm::Value* inc = builder->CreateAdd(val, llvm::ConstantInt::get(*context, llvm::APInt(32, 1)), "inc");
+        builder->CreateStore(inc, alloca);
+        
+    } else if (auto getProp = dynamic_cast<GetPropExpr*>(node.variable.get())) {
+        getProp->object->accept(*this);
+        llvm::Value* objectPtr = lastValue;
+        std::string className = lastClassName;
+        
+        if (!objectPtr) return;
+        
+        if (classFields.find(className) == classFields.end()) {
+             std::cerr << "Unknown class type: " << className << std::endl;
+             lastValue = nullptr;
+             return;
+        }
+
+        const auto& fields = classFields[className];
+        int fieldIndex = -1;
+        for (size_t i = 0; i < fields.size(); ++i) {
+            if (fields[i] == getProp->name) {
+                fieldIndex = i;
+                break;
+            }
+        }
+
+        if (fieldIndex == -1) {
+            std::cerr << "Unknown field: " << getProp->name << " in class " << className << std::endl;
+            lastValue = nullptr;
+            return;
+        }
+
+        std::vector<llvm::Value*> indices;
+        indices.push_back(llvm::ConstantInt::get(*context, llvm::APInt(32, 0)));
+        indices.push_back(llvm::ConstantInt::get(*context, llvm::APInt(32, fieldIndex)));
+
+        llvm::Type* structType = classStructs[className];
+        llvm::Value* fieldPtr = builder->CreateGEP(structType, objectPtr, indices, "fieldptr");
+        
+        llvm::Value* val = builder->CreateLoad(llvm::Type::getInt32Ty(*context), fieldPtr, "fieldval");
+        lastValue = val;
+        
+        llvm::Value* inc = builder->CreateAdd(val, llvm::ConstantInt::get(*context, llvm::APInt(32, 1)), "inc");
+        builder->CreateStore(inc, fieldPtr);
+
+    } else if (auto indexExpr = dynamic_cast<IndexExpr*>(node.variable.get())) {
+        indexExpr->array->accept(*this);
+        llvm::Value* arrPtr = lastValue;
+        
+        indexExpr->index->accept(*this);
+        llvm::Value* indexVal = lastValue;
+        
+        llvm::Function* getFn = module->getFunction("sun_array_get");
+        llvm::Function* setFn = module->getFunction("sun_array_set");
+        
+        llvm::Value* valPtr = builder->CreateCall(getFn, {arrPtr, indexVal}, "elem");
+        // Assume IntArray for increment
+        llvm::Value* val = builder->CreatePtrToInt(valPtr, llvm::Type::getInt32Ty(*context), "elemInt");
+        lastValue = val;
+        
+        llvm::Value* inc = builder->CreateAdd(val, llvm::ConstantInt::get(*context, llvm::APInt(32, 1)), "inc");
+        
+        // Store back
+        llvm::Value* voidVal = builder->CreateIntToPtr(inc, llvm::PointerType::get(llvm::Type::getInt8Ty(*context), 0));
+        builder->CreateCall(setFn, {arrPtr, indexVal, voidVal});
+    } else {
+        std::cerr << "Invalid increment target." << std::endl;
+        lastValue = nullptr;
+    }
+}
+
 void CodeGen::visit(BinaryExpr& node) {
     node.left->accept(*this);
     llvm::Value* L = lastValue;
@@ -311,6 +392,12 @@ void CodeGen::visit(BinaryExpr& node) {
     } else if (node.op == ">") {
         lastValue = builder->CreateICmpSGT(L, R, "cmptmp");
         lastValue = builder->CreateIntCast(lastValue, llvm::Type::getInt32Ty(*context), true, "booltmp");
+    } else if (node.op == "<=") {
+        lastValue = builder->CreateICmpSLE(L, R, "cmptmp");
+        lastValue = builder->CreateIntCast(lastValue, llvm::Type::getInt32Ty(*context), true, "booltmp");
+    } else if (node.op == ">=") {
+        lastValue = builder->CreateICmpSGE(L, R, "cmptmp");
+        lastValue = builder->CreateIntCast(lastValue, llvm::Type::getInt32Ty(*context), true, "booltmp");
     } else if (node.op == "==") {
         lastValue = builder->CreateICmpEQ(L, R, "cmptmp");
         lastValue = builder->CreateIntCast(lastValue, llvm::Type::getInt32Ty(*context), true, "booltmp");
diff --git a/src/codegen.h b/src/codegen.h
index dbcfb82..8b0d284 100644
--- a/src/codegen.h
+++ b/src/codegen.h
@@ -28,6 +28,7 @@ public:
     void visit(ArrayExpr& node) override;
     void visit(IndexExpr& node) override;
     void visit(ArrayAssignExpr& node) override;
+    void visit(IncrementExpr& node) override;
     void visit(BinaryExpr& node) override;
     void visit(ReturnStmt& node) override;
     void visit(VarDeclStmt& node) override;
diff --git a/src/lexer.cpp b/src/lexer.cpp
index 138aa56..c493717 100644
--- a/src/lexer.cpp
+++ b/src/lexer.cpp
@@ -107,7 +107,12 @@ Token Lexer::scanToken() {
         case '.': return makeToken(TokenType::DOT, ".");
         case ':': return makeToken(TokenType::COLON, ":");
         case ';': return makeToken(TokenType::SEMICOLON, ";");
-        case '+': return makeToken(TokenType::PLUS, "+");
+        case '+': 
+            if (peek() == '+') {
+                advance();
+                return makeToken(TokenType::PLUS_PLUS, "++");
+            }
+            return makeToken(TokenType::PLUS, "+");
         case '-': return makeToken(TokenType::MINUS, "-");
         case '*': return makeToken(TokenType::STAR, "*");
         case '/': 
@@ -122,8 +127,18 @@ Token Lexer::scanToken() {
                 return makeToken(TokenType::EQUAL_EQUAL, "==");
             }
             return makeToken(TokenType::EQUALS, "=");
-        case '<': return makeToken(TokenType::LESS, "<");
-        case '>': return makeToken(TokenType::GREATER, ">");
+        case '<': 
+            if (peek() == '=') {
+                advance();
+                return makeToken(TokenType::LESS_EQUAL, "<=");
+            }
+            return makeToken(TokenType::LESS, "<");
+        case '>': 
+            if (peek() == '=') {
+                advance();
+                return makeToken(TokenType::GREATER_EQUAL, ">=");
+            }
+            return makeToken(TokenType::GREATER, ">");
         case '"': return string();
         default:  return makeToken(TokenType::UNKNOWN, std::string(1, c));
     }
diff --git a/src/parser.cpp b/src/parser.cpp
index 44bfaf1..dedaacb 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -366,7 +366,7 @@ std::unique_ptr<Expr> Parser::equality() {
 std::unique_ptr<Expr> Parser::comparison() {
     std::unique_ptr<Expr> expr = term();
 
-    while (match(TokenType::LESS) || match(TokenType::GREATER)) {
+    while (match(TokenType::LESS) || match(TokenType::GREATER) || match(TokenType::LESS_EQUAL) || match(TokenType::GREATER_EQUAL)) {
         std::string op = previous().value;
         std::unique_ptr<Expr> right = term();
         expr = std::make_unique<BinaryExpr>(std::move(expr), op, std::move(right));
@@ -410,6 +410,8 @@ std::unique_ptr<Expr> Parser::call() {
             std::unique_ptr<Expr> index = expression();
             consume(TokenType::RBRACKET, "Expect ']' after index.");
             expr = std::make_unique<IndexExpr>(std::move(expr), std::move(index));
+        } else if (match(TokenType::PLUS_PLUS)) {
+            expr = std::make_unique<IncrementExpr>(std::move(expr));
         } else {
             break;
         }
diff --git a/src/token.h b/src/token.h
index d869176..e5346a8 100644
--- a/src/token.h
+++ b/src/token.h
@@ -41,6 +41,9 @@ enum class TokenType {
     EQUAL_EQUAL,// ==
     LESS,       // <
     GREATER,    // >
+    LESS_EQUAL, // <=
+    GREATER_EQUAL, // >=
+    PLUS_PLUS,  // ++
     END_OF_FILE,
     UNKNOWN
 };
diff --git a/src/version.h b/src/version.h
index a8ec32d..e0dc157 100644
--- a/src/version.h
+++ b/src/version.h
@@ -1,6 +1,6 @@
 #ifndef SUN_VERSION_H
 #define SUN_VERSION_H
 
-#define SUN_VERSION "0.3.1"
+#define SUN_VERSION "0.4.0"
 
 #endif // SUN_VERSION_H
diff --git a/sun b/sun
index 6af4459..f720881 100755
Binary files a/sun and b/sun differ
diff --git a/tests/test_for.sun b/tests/test_for.sun
index 7f57a4a..d6b1697 100644
--- a/tests/test_for.sun
+++ b/tests/test_for.sun
@@ -1,7 +1,4 @@
-function main() {
-  print("Counting:");
-  for (var i = 0; i < 5; i = i + 1) {
-    print(i);
-  }
-  return 0;
+print("Counting:");
+for (var i = 0; i <= 5; i++) {
+  print(i);
 }
\ No newline at end of file