From e77d832dcb92abc98e208f73aa8136736526f7fb Mon Sep 17 00:00:00 2001
From: hthuz <hanggang.20@intl.zju.edu.cn>
Date: Wed, 11 Sep 2024 22:56:42 +0800
Subject: [PATCH] add: c++ virtual override

---
 .gitignore       |  2 --
 cpp/override.cpp | 23 +++++++++++++++++++++++
 cpp/string.cpp   | 26 ++++++++++++++++++++++++++
 3 files changed, 49 insertions(+), 2 deletions(-)
 create mode 100644 cpp/override.cpp
 create mode 100644 cpp/string.cpp

diff --git a/.gitignore b/.gitignore
index 05fd24c..62014db 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,8 +2,6 @@
 c/*.out
 c/*.o
 cpp/*.out
-cpp/
-!cpp/*.cpp
 
 
 java/*.class
diff --git a/cpp/override.cpp b/cpp/override.cpp
new file mode 100644
index 0000000..8c89640
--- /dev/null
+++ b/cpp/override.cpp
@@ -0,0 +1,23 @@
+
+#include <iostream>
+
+
+class Expression_class {
+public:
+	// Without virtual, the program will gives 0; => Based on declared type
+	// With virtual => Based on derived classes
+	virtual bool is_no_expr() {return false;}
+};
+
+typedef Expression_class* Expression;
+
+class no_expr_class : public Expression_class {
+public:
+	bool is_no_expr() {return true;}
+};
+
+int main() {
+	// Compiler makes decision based on static type information available at compile time
+	Expression expr = new no_expr_class();
+	std::cout << expr->is_no_expr() << std::endl;
+}
diff --git a/cpp/string.cpp b/cpp/string.cpp
new file mode 100644
index 0000000..454bc6d
--- /dev/null
+++ b/cpp/string.cpp
@@ -0,0 +1,26 @@
+
+#include <iostream>
+#include <string>
+using namespace std;
+
+int main() {
+	string str;
+	str = "amazing";
+	cout << str << endl;
+	str = "amaz\"ing";
+	cout << str << endl;
+	str = "amaz\"in\"g";
+	cout << str << endl;
+	str = "amazi""ng";
+	cout << str << endl;
+	str = "amaz'ing";
+	cout << str << endl;
+	str = "ama'z'ing";
+	cout << str << endl;
+	str = "ama\'zing";
+	cout << str << endl;
+
+	
+
+}
+