Create stopwatch with C++

This is going to be a mini project in c++

C++ is a great language but to make something using it is a bit difficult. But that doesn't mean you can't do anything with it. You can create small console based applications and that's what we are going to do. I will show you how to create a simple stopwatch with C++.

I got this idea from my javascript stopwatch project and thought how can I create something like that in C++. So let's see how to do it !!

Requirements

• C++ compiler (or you can use any online platform. My recommendation is: Repl.it)
• Text editor
• Some knowledge of C++

Step 1: Write the base code

We will start by writing the base code for our console application.

• Create a folder and give it a name. e.g. cpp-stopwatch
• Create a file named stopwatch.cpp in that folder.

// stopwatch.cpp #include <iostream>  using namespace std; int main() { cout << "stopwatch" << endl; } 

• To compile and run this code, open your terminal or command prompt and navigate to that folder and run the following commands

# compile g++ stopwatch.cpp -o stopwatch # run  ./stopwatch 

Use these commands every time you make changes to your C++ file.

Step 2: Displaying our stopwatch

First we will start by displaying our stopwatch in console before adding functionality to it. For that we will create necessary variables and a function named displayTime to display our stopwatch.

// stopwatch.cpp #include <iostream>  using namespace std; void displayTime(int hours, int minutes, int seconds) { cout << hours << ":" << minutes << ":" << seconds << endl; } int main() { int hour = 0; int min = 0; int sec = 0; displayTime(hour, min, sec); } 

Step 3: Stopwatch functionality !!

Now the interesting part, functioning of stopwatch. If you are familiar with javascript, you already know that there is a built-in function setInterval that runs the code after the specified interval. But how can we do that thing in C++ ??

In C++ we can use a function called sleep which is available in the header unistd.h in linux and windows.h in windows.

Sleep function takes number of seconds and stops the code for the specified duration.

#include <iostream> #include <unistd.h> // in linux: sleep()  // #include <windows.h> // in windows: Sleep() using namespace std; int main() { cout << "wait for 5 seconds !" << endl; sleep(5); cout << "5 seconds passed away !" << endl; } 

So, we have a way to stop our code but we need a way to increment number of seconds continuously. For that we will use LOOOOOP.

#include <iostream> #include <unistd.h> // in linux: sleep()  // #include <windows.h> // in windows: Sleep() using namespace std; int main() { int hour = 0; int min = 0; int sec = 0; // run the stopwatch continuously while(true) { sleep(1); sec++; cout << sec << endl; } } 

Let's add the code for hours and minutes as well and also use our display function

#include <iostream> #include <unistd.h> // in linux: sleep()  // #include <windows.h> // in windows: Sleep() using namespace std; void displayTime(int hours, int minutes, int seconds) { cout << hours << ":" << minutes << ":" << seconds << endl; } int main() { int hour = 0; int min = 0; int sec = 0; while(true) { sleep(1); sec++; if(sec > 59) { min++; sec = 0; } if(min > 59) { hour++; sec = 0; min = 0; } displayTime(hour, min, sec); } } 

Running this code will start printing stopwatch with new time, line by line. We can handle this by simple clearing screen before displaying the next time.

• Add system("clear") in displayTime function
• We will also display initial time before entering the loop so that stopwatch display time from 0 hours, 0 minutes and 0 seconds instead of directly showing 1 second in console

#include <iostream> #include <unistd.h> // in linux: sleep()  // #include <windows.h> // in windows: Sleep() using namespace std; void displayTime(int hours, int minutes, int seconds) { // for linux system("clear"); // for windows // system("cls"); cout << hours << ":" << minutes << ":" << seconds << endl; } int main() { int hour = 0; int min = 0; int sec = 0; displayTime(hour, min, sec); while(true) { sleep(1); sec++; if(sec > 59) { min++; sec = 0; } if(min > 59) { hour++; sec = 0; min = 0; } displayTime(hour, min, sec); } } 

Finally, compile and run it and hopefully you will see your very own console stopwatch. To stop the stopwatch, use Ctrl + C

This one was beginner friendly and doesn't use threads and chrono library. You can find the source code and working example in my repl.

I am not an expert in C++ but trying new things and applying them is important. Hope you learned something new out of this simple C++ stopwatch project.