// プログラムの中で使う機能の事前セッティングみたいなもの
#include <iostream>
#include <vector>
#include <thread>
#include <mutex>

std::mutex cout_mutex;

// 【1】同時実行される小プログラム
void executeActivity(const std::string& activity) {
    std::lock_guard<std::mutex> lock(cout_mutex);
    std::cout << "*" << activity << " [Thread: " << std::this_thread::get_id() << "]\n";
}

// 【2】メインプログラム（ここから始まる）
int main() {
    // 【3】同時実行されるときに使われる、生活単語
    std::vector<std::string> activities = {
        "Clock Out", "Return Home", "Recharge (Liquid Debugging)", "Bath",
        "Dinner", "Stretch", "Read Book", "Sleep"
    };
    
    // 【4】同時実行を管理する変数
    std::vector<std::thread> threads;
        
        // 【5】生活単語の数だけ、同時実行プログラムをセッティング
        for (const auto& activity : activities) {
            threads.emplace_back(executeActivity, activity);
        }
    
    // 【6】同時実行開始（それぞれの実行順序は、毎回異なる。陸上競技のスタートみたいなもの）
    for (auto& thread : threads) {
        thread.join();
    }

    {
        std::lock_guard<std::mutex> lock(cout_mutex);
                // ↑ この lock() を行うことで、
                // 一斉に表示しようとして表示が入り乱れるのを防いでいる。
                // 小プログラムの中でも同じことが行われている。
        std::cout << "[System] All tasks completed.\n";
    }

    return 0;
}
/*
いろいろな生活単語を表示する小プログラムを『同時に実行』するが、
表示は入り乱れたりせず、きれいに表示される。
ということを示したプログラムと言えます。
*/
by

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
}