// Including the necessary libraries for ImGui and OpenGL.
include <imgui.h>
include <imgui_impl_glfw.h>
include <imgui_impl_opengl3.h>
include <GLFW/glfw3.h>

// Function to initialize ImGui and OpenGL.
void InitImGui(GLFWwindow* window) {
    // Setup ImGui context.
    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    ImGuiIO& io = ImGui::GetIO();
    (void)io;

    // Setup ImGui style.
    ImGui::StyleColorsDark();

    // Setup Platform/Renderer bindings.
    ImGui_ImplGlfw_InitForOpenGL(window, true);
    ImGui_ImplOpenGL3_Init("#version 330");
}

// Function to cleanup ImGui and OpenGL resources.
void CleanupImGui() {
    ImGui_ImplOpenGL3_Shutdown();
    ImGui_ImplGlfw_Shutdown();
    ImGui::DestroyContext();
}

// Function to render the ImGui menu.
void RenderImGuiMenu() {
    // Start the ImGui frame.
    ImGui_ImplOpenGL3_NewFrame();
    ImGui_ImplGlfw_NewFrame();
    ImGui::NewFrame();

    // Create a window for the login menu.
    ImGui::Begin("Login Menu");

    // Add UI elements for username and password input.
    static char username[32] = "";
    static char password[32] = "";
    ImGui::InputText("Username", username, IM_ARRAYSIZE(username));
    ImGui::InputText("Password", password, IM_ARRAYSIZE(password), ImGuiInputTextFlags_Password);

    // Add a button for login.
    if (ImGui::Button("Login")) {
        // Perform login logic here.
        // For example, you can check if the username and password are valid and display a message accordingly.
        if (strcmp(username, "admin") == 0 && strcmp(password, "password") == 0) {
            ImGui::Text("Login successful!");
        } else {
            ImGui::Text("Invalid username or password.");
        }
    }

    ImGui::End();

    // Render ImGui.
    ImGui::Render();
    ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
}

int main() {
    // Initialize GLFW and create a window.
    glfwInit();
    GLFWwindow* window = glfwCreateWindow(800, 600, "ImGui Menu", nullptr, nullptr);
    glfwMakeContextCurrent(window);

    // Initialize ImGui and OpenGL.
    InitImGui(window);

    // Main loop.
    while (!glfwWindowShouldClose(window)) {
        // Process events.
        glfwPollEvents();

        // Clear the screen.
        glClear(GL_COLOR_BUFFER_BIT);

        // Render the ImGui menu.
        RenderImGuiMenu();

        // Swap buffers.
        glfwSwapBuffers(window);
    }

    // Cleanup ImGui and OpenGL resources.
    CleanupImGui();

    // Terminate GLFW.
    glfwTerminate();

    return 0;
}

C++ Online Compiler

Write, Run & Share C++ code online using OneCompiler's C++ online compiler for free. It's one of the robust, feature-rich online compilers for C++ language, running on the latest version 17. Getting started with the OneCompiler's C++ compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C++ and start coding!

Read inputs from stdin

OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.

#include <iostream>
#include <string>
using namespace std;

int main() 
{
    string name;
    cout << "Enter name:";
    getline (cin, name);
    cout << "Hello " << name;
    return 0;
}

About C++

C++ is a widely used middle-level programming language.

  • Supports different platforms like Windows, various Linux flavours, MacOS etc
  • C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
  • Case-sensitive
  • C++ is a compiler based language
  • C++ supports structured programming language
  • C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
  • Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}