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How to use gdb in Ubuntu Terminal

Here's a practical, minimal guide for using GDB in Ubuntu terminal — from launching to setting breakpoints and navigating your code. 🧰 Step 1: Compile with Debug Symbols Use -g and disable optimizations ( -O0 preferred for debugging): bash Copy Edit g++ -g -O0 -o myprog myprog.cpp 🚀 Step 2: Launch GDB bash Copy Edit gdb ./myprog You'll see a (gdb) prompt. 🎯 Step 3: Set Breakpoints You can set breakpoints in three main ways : ✅ a. At a function gdb Copy Edit (gdb) break main ✅ b. At a specific file and line gdb Copy Edit (gdb) break myprog.cpp:42 ✅ c. At a method in a class gdb Copy Edit (gdb) break MyClass::doSomething If the symbol is mangled (C++), GDB usually demangles automatically, especially if compiled with -g . ▶️ Step 4: Run the Program gdb Copy Edit (gdb) run 🧭 Step 5: Navigate Command Meaning next or n Step over current line step or s Step into function call finish Run until current function returns continue or c Continue until...
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Uninstall Postgresql completely from ubuntu 24

You said: uninstall postgres completely from ubuntu ChatGPT said: ChatGPT To completely uninstall PostgreSQL from your Ubuntu system, including removing all associated data and configuration files, follow these steps: 1. Stop PostgreSQL Service First, stop any running PostgreSQL services before uninstalling. bash Copy code sudo systemctl stop postgresql 2. Remove PostgreSQL Packages Use apt to remove PostgreSQL packages, including client libraries and server binaries. bash Copy code sudo apt-get --purge remove postgresql postgresql-* libpq-dev The --purge option ensures that configuration files are also removed. 3. Remove PostgreSQL Data Directory PostgreSQL data (such as databases and logs) is stored in /var/lib/postgresql by default. Remove this directory to delete all databases and related data. bash Copy code sudo rm -rf /var/lib/postgresql/ 4. Remove PostgreSQL Configuration Files PostgreSQL configuration files are stored in /etc/postgresql . Remove this directory to delete al...
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C++ tricks Class constructor / object initialization discussions with chatGpt

  class XXX{       int a;       long b;       std::string c;     public:       XXX(const int&a,const long&b,const std::string&c):a(a),b(b),c(c){}     };      class YYY{       int a;     public:       YYY(const int&a):a(a){}     };     void fn(){       std::vector<XXX> vec{{4, 5, "aa"}};       std::vector<XXX> vec0{4, 5, "aa",10,8,"cc"};       std::vector<YYY>vec2{4,5,6,8,10};     } vec,vec2 working, but vec0 not working -------------------------------------------- The issue with vec0 is related to how you're trying to initialize the vector of XXX objects. When you attempt: cpp Copy code std::vector<XXX> vec0{ 4 , 5 , "aa" , 10 , 8 , "cc" }; you're providing multiple arguments, but this syntax doesn't match the expected initialization ...
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Structure/Class padding in C/C++ (chatGpt discussions)

In structure there's structre padding. Any such thing in class? ChatGPT said: ChatGPT Yes, structure padding occurs in both C-style structs and C++ classes . Padding is introduced by the compiler to ensure proper alignment of data members in memory, and it applies to classes in C++ just as it does to structures. Key Points about Padding: Alignment: Different data types have different alignment requirements. For example, int may need to be aligned on 4-byte boundaries, and double may need 8-byte boundaries. The compiler adds padding between data members to align them properly. Padding in C++ Classes: C++ classes follow the same memory layout and alignment rules as C-style structs. If a class contains multiple data members, the compiler may insert padding between members to meet alignment requirements. Padding is also added at the end of the structure/class to ensure the entire object meets the alignment requirement of the largest member. Example: cpp Copy code # include <ios...
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