#include <iostream>
#include <cmath>
using namespace std;

#define real_t float

struct vector2 {
  union {
  	struct {
	  	union {
		  	real_t x;
		  	real_t width;
		};
  		union {
	  		real_t y;
	  		real_t height;
  		};
  	};
  	real_t coord[2] = { 0 };
  };
  vector2() {}
  vector2(const real_t p_x, const real_t p_y) {
		x = p_x;
		y = p_y;
	}
  void print() {
    cout << "(" << x << ";" << y << ")" << endl;
  }
  void normalize() {
	  real_t l = x * x + y * y;
	  if (l != 0) {
		  l = sqrt(l);
		  x /= l;
		  y /= l;
	  }
  }
  vector2 normalized() {
	  vector2 v = *this;
	  v.normalize();
	  return v;
  }
};

vector2 test(vector2 v) {
  v.width = 20;
  v.coord[1] = 55;
  return v;
}

int main() {
  vector2 vec; vec.print();
  test(vec).print();
  test(vec); vec.print();
  vec = test(vec); vec.print();
  vec = vec.normalized(); vec.print();
  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
}