#include <iostream>
#include <ctime>
#include <chrono>
#include <thread>
#include <cstdlib>

using namespace std;

void displayTime() {
    while (true) {
        system("clear");  // Use "cls" instead of "clear" on Windows
        time_t now = time(0);
        tm* localTime = localtime(&now);

        cout << "Current Time: ";
        cout << localTime->tm_hour << ":" << localTime->tm_min << ":" << localTime->tm_sec << endl;

        this_thread::sleep_for(chrono::seconds(1));
    }
}

void setAlarm(int hour, int minute) {
    time_t now;
    tm alarmTime = {};
    alarmTime.tm_hour = hour;
    alarmTime.tm_min = minute;

    while (true) {
        now = time(0);
        tm* localTime = localtime(&now);

        if (localTime->tm_hour == alarmTime.tm_hour && localTime->tm_min == alarmTime.tm_min) {
            cout << "ALARM: Time to wake up!" << endl;
            for (int i = 0; i < 5; i++) {
                cout << '\a';  // Beep the terminal (may not work on all systems)
                this_thread::sleep_for(chrono::seconds(1));
            }
            break;
        }

        this_thread::sleep_for(chrono::seconds(1));
    }
}

int main() {
    thread clockThread(displayTime);

    int alarmHour, alarmMinute;
    cout << "Enter the alarm time (HH MM): ";
    cin >> alarmHour >> alarmMinute;

    setAlarm(alarmHour, alarmMinute);

    clockThread.join();
    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
}