// C++ program for implementing
// Mid-Point Circle Drawing Algorithm
#include<iostream>
using namespace std;

// Implementing Mid-Point Circle Drawing Algorithm
void midPointCircleDraw(int x_centre, int y_centre, int r)
{
	int x = r, y = 0;
	
	// Printing the initial point on the axes
	// after translation
	cout << "(" << x + x_centre << ", " << y + y_centre << ") ";
	
	// When radius is zero only a single
	// point will be printed
	if (r > 0)
	{
		cout << "(" << x + x_centre << ", " << -y + y_centre << ") ";
		cout << "(" << y + x_centre << ", " << x + y_centre << ") ";
		cout << "(" << -y + x_centre << ", " << x + y_centre << ")\n";
	}
	
	// Initialising the value of P
	int P = 1 - r;
	while (x > y)
	{
		y++;
		
		// Mid-point is inside or on the perimeter
		if (P <= 0)
			P = P + 2*y + 1;
		// Mid-point is outside the perimeter
		else
		{
			x--;
			P = P + 2*y - 2*x + 1;
		}
		
		// All the perimeter points have already been printed
		if (x < y)
			break;
		
		// Printing the generated point and its reflection
		// in the other octants after translation
		cout << "(" << x + x_centre << ", " << y + y_centre << ") ";
		cout << "(" << -x + x_centre << ", " << y + y_centre << ") ";
		cout << "(" << x + x_centre << ", " << -y + y_centre << ") ";
		cout << "(" << -x + x_centre << ", " << -y + y_centre << ")\n";
		
		// If the generated point is on the line x = y then
		// the perimeter points have already been printed
		if (x != y)
		{
			cout << "(" << y + x_centre << ", " << x + y_centre << ") ";
			cout << "(" << -y + x_centre << ", " << x + y_centre << ") ";
			cout << "(" << y + x_centre << ", " << -x + y_centre << ") ";
			cout << "(" << -y + x_centre << ", " << -x + y_centre << ")\n";
		}
	}
}

// Driver code
int main()
{
	// To draw a circle of radius 3 centered at (0, 0)
	midPointCircleDraw(0, 0, 3);
	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
}