feat(c++): destructor and memory leak example

.gitignore

@@ -1 +1,2 @@
-**/output/**
+**/output/**
+/backup/**

.vscode/settings.json

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+{
+    "files.associations": {
+        "__bit_reference": "cpp",
+        "__bits": "cpp",
+        "__config": "cpp",
+        "__debug": "cpp",
+        "__errc": "cpp",
+        "__hash_table": "cpp",
+        "__locale": "cpp",
+        "__mutex_base": "cpp",
+        "__node_handle": "cpp",
+        "__nullptr": "cpp",
+        "__split_buffer": "cpp",
+        "__string": "cpp",
+        "__threading_support": "cpp",
+        "__tuple": "cpp",
+        "array": "cpp",
+        "atomic": "cpp",
+        "bitset": "cpp",
+        "cctype": "cpp",
+        "chrono": "cpp",
+        "clocale": "cpp",
+        "cmath": "cpp",
+        "compare": "cpp",
+        "complex": "cpp",
+        "concepts": "cpp",
+        "cstdarg": "cpp",
+        "cstddef": "cpp",
+        "cstdint": "cpp",
+        "cstdio": "cpp",
+        "cstdlib": "cpp",
+        "cstring": "cpp",
+        "ctime": "cpp",
+        "cwchar": "cpp",
+        "cwctype": "cpp",
+        "exception": "cpp",
+        "initializer_list": "cpp",
+        "ios": "cpp",
+        "iosfwd": "cpp",
+        "iostream": "cpp",
+        "istream": "cpp",
+        "limits": "cpp",
+        "locale": "cpp",
+        "memory": "cpp",
+        "mutex": "cpp",
+        "new": "cpp",
+        "optional": "cpp",
+        "ostream": "cpp",
+        "ratio": "cpp",
+        "sstream": "cpp",
+        "stdexcept": "cpp",
+        "streambuf": "cpp",
+        "string": "cpp",
+        "string_view": "cpp",
+        "system_error": "cpp",
+        "tuple": "cpp",
+        "type_traits": "cpp",
+        "typeinfo": "cpp",
+        "unordered_map": "cpp",
+        "variant": "cpp",
+        "vector": "cpp",
+        "algorithm": "cpp"
+    }
+}

c++/cpp-destructor-and-memory-leak/ex1.cpp

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+#include <iostream>
+
+class One {
+    public:
+        One() {};
+        ~One() {
+            std::cout<<"Destroying One"<<std::endl;
+        };
+};
+
+class Two {
+    private:
+        One* one;
+    public:
+        Two() {
+            one = new One();
+        };
+        ~Two() {
+            // delete one;
+            std::cout<<"Destroying Two"<<std::endl;
+        };
+};
+
+void doSomething() {
+    Two two;
+    // ...
+    return;
+    // [출력] Destroying Two
+}
+
+int main(void)
+{
+    std::cout<<"Before doSomething"<<std::endl;
+    doSomething();
+    std::cout<<"After doSomething"<<std::endl;
+    return 0;
+}

c++/cpp-destructor-and-memory-leak/ex2.cpp

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+#include <iostream>
+
+class One {
+    public:
+        One() {};
+        ~One() {
+            std::cout<<"Destroying One"<<std::endl;
+        };
+};
+
+class Two {
+    private:
+        One* one;
+    public:
+        Two() {
+            one = new One();
+        };
+        ~Two() {
+            delete one;
+            std::cout<<"Destroying Two"<<std::endl;
+        };
+};
+
+void doSomething() {
+    Two two;
+    // ...
+    return; 
+    // [출력] Destroying One
+    // [출력] Destroying Two
+}
+
+int main(void)
+{
+    std::cout<<"Before doSomething"<<std::endl;
+    doSomething();
+    std::cout<<"After doSomething"<<std::endl;
+    return 0;
+}

c++/cpp-destructor-and-memory-leak/ex3.cpp

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+#include <iostream>
+#include <cstring>
+
+class First {
+    private:
+        char* str1;
+    public:
+        First(char* str) {
+            this->str1=new char[strlen(str)+1];
+            strcpy(this->str1, str);
+        };
+        ~First() {
+            std::cout<<"Destroying First"<<std::endl;
+            std::cout<<"Destroying '"<<str1<<"'"<<std::endl;
+            delete []str1;
+        };
+};
+
+class Second : public First {
+    private:
+        char* str2;
+    public:
+        Second(char* str1, char* str2) : First(str1) {
+            this->str2=new char[strlen(str2)+1];
+            strcpy(this->str2, str2);
+        };
+        ~Second() {
+            std::cout<<"Destroying Second"<<std::endl;
+            std::cout<<"Destroying '"<<str2<<"'"<<std::endl;
+            delete []str2;
+        };
+};
+
+int main(void)
+{
+    Second* second = new Second("one", "two");
+    delete second;
+    // [출력] Destroying Second
+    // [출력] Destroying 'two'
+    // [출력] Destroying First
+    // [출력] Destroying 'one'
+
+    std::cout<<"==================="<<std::endl;
+
+    First* first = new Second("one", "two");
+    delete first;
+    // [출력] Destroying First
+    // [출력] Destroying 'one'
+    return 0;
+}

c++/cpp-destructor-and-memory-leak/ex4.cpp

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+#include <iostream>
+#include <cstring>
+
+class First {
+    private:
+        char* str1;
+    public:
+        First(char* str) {
+            this->str1=new char[strlen(str)+1];
+            strcpy(this->str1, str);
+        };
+        virtual ~First() {
+            std::cout<<"Destroying First"<<std::endl;
+            std::cout<<"Destroying '"<<str1<<"'"<<std::endl;
+            delete []str1;
+        };
+};
+
+class Second : public First {
+    private:
+        char* str2;
+    public:
+        Second(char* str1, char* str2) : First(str1) {
+            this->str2=new char[strlen(str2)+1];
+            strcpy(this->str2, str2);
+        };
+        ~Second() {
+            std::cout<<"Destroying Second"<<std::endl;
+            std::cout<<"Destroying '"<<str2<<"'"<<std::endl;
+            delete []str2;
+        };
+};
+
+int main(void)
+{
+    First* first = new Second("one", "two");
+    delete first;
+    // [출력] Destroying Second
+    // [출력] Destroying 'two'
+    // [출력] Destroying First
+    // [출력] Destroying 'one'
+    return 0;
+}