#include <chrono>
#include <iostream>
#include <iomanip>
#include <sstream>

using Clock = std::chrono::high_resolution_clock;
static std::string timePointToString(const Clock::time_point &tp, const std::string &format, bool withMs = true, bool utc = true)
{
	const Clock::time_point::duration tt = tp.time_since_epoch();
	const time_t durS = std::chrono::duration_cast<std::chrono::seconds>(tt).count();
	std::ostringstream ss;
	std::tm tm;
	if ((utc ? gmtime_s(&durS, &tm) : localtime_s(&durS, &tm)) != nullptr) {
		ss << std::put_time(&tm, format.c_str());
		if (withMs) {
			const long long durMs = std::chrono::duration_cast<std::chrono::milliseconds>(tt).count();
			ss << std::setw(3) << std::setfill('0') << int(durMs - durS * 1000);
		}
	}
	// gmtime/localtime() returned null
	else {
		ss << "<FORMAT ERROR>";
	}
	return ss.str();
}

int main() {
	const auto tp = Clock::now();
	std::cout << timePointToString(tp, "%Z %Y-%m-%d %H:%M:%S.") << std::endl;
    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
}