#include <iostream>
#include <string>
#include <thread>
#include <mutex>
#include <queue>
#include <atomic>
#include <condition_variable>
 
class Q {
private:
    std::mutex _mutex;
    std::condition_variable _cv;
    std::queue<std::string> _queue;
    std::atomic_bool _stop = false;
    std::thread _thread;
public:    

    Q () {
        _thread = std::thread([this]() { worker_main(); });
    }
    
    ~Q () {
        if (_thread.joinable()) {
            stop();
            _thread.join();
        }
    }
    
    void stop() {
        {
            std::lock_guard lock(_mutex);
            _stop = true;
        }
        _cv.notify_all();
    }

    void push(const std::string& s) {
        {
            std::lock_guard lk(_mutex);
            _queue.push(s);
        }
        _cv.notify_one();
    }

    void worker_main()
    {
        bool stop = false;
        do
        {
            std::queue<std::string> q;
            std::unique_lock lk(_mutex);
            _cv.wait(lk,[this](){return _stop||!_queue.empty();});
            stop = _stop; //get stop gignal
            std::swap(_queue, q); //move/swap queue items
            lk.unlock();
            //handle chunk of items...
            while (!q.empty()) {
                std::cout << q.front() << std::endl;
                q.pop();
            }
        }
        while (!stop);
    }
 };
 
 
 
int main()
{
    {   
        Q q;
        q.push("1 12345");
        std::this_thread::yield();
        q.push("2 67890");
        std::this_thread::yield();
        q.push("3 abcde");
        std::this_thread::yield();
        q.push("4 fghij");
        std::this_thread::yield();
        q.push("5 12345");
        std::this_thread::yield();
        q.push("6 67890");
        std::this_thread::yield();
        q.push("7 abcde");
        std::this_thread::yield();
        q.push("8 fghij");
        std::this_thread::yield();
        q.push("-end-");
        std::this_thread::yield();
    }
}

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
}