#include <GL/glut.h> // GLUT, include glu.h and gl.h
/* Initialize OpenGL Graphics */
void init(void)
{
glClearColor(0.0,0.0,0.0,1.0);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(-100,100,-100,100);
}
/* Handler for window-repaint event. Call back when the window first appears and
 whenever the window needs to be re-painted. */
void display() {
 glClear(GL_COLOR_BUFFER_BIT); 
glPointSize(4.0f);
glBegin(GL_LINES); 
 
 glVertex2f(-100.0f, 0.0f);
 glVertex2f(100.0f, 0.0f);
 
 glVertex2f(0.0f, 100.0f);
 glVertex2f(0.0f, -100.0f);
 
 glEnd();
glBegin(GL_LINE_LOOP); 
 glColor3f(1.0f, 0.0f, 5.0f); 
 glVertex2f(10.0f, 10.0f);
 glVertex2f(40.0f, 10.0f);
 
 glVertex2f(40.0f, 40.0f);
 glVertex2f(10.0f, 40.0f);
 
 glEnd();
glBegin(GL_LINE_LOOP); 
 glColor3f(1.0f, 0.0f, 5.0f); 
 glVertex2f(25.0f, 25.0f);
 glVertex2f(55.0f, 25.0f);
 glVertex2f(55.0f, 55.0f);
 glVertex2f(25.0f, 55.0f);
 
 glEnd();
glBegin(GL_LINES); 
 glColor3f(1.0f, 0.0f, 5.0f); 
 glVertex2f(10.0f, 10.0f);
glVertex2f(25.0f, 25.0f);
 glVertex2f(40.0f, 10.0f);
 glVertex2f(55.0f, 25.0f);
 glVertex2f(40.0f, 40.0f);
glVertex2f(55.0f, 55.0f);
 glVertex2f(10.0f, 40.0f);
glVertex2f(25.0f, 55.0f);
glEnd();
 glFlush(); // Render now
}
/* Main function: GLUT runs as a console application starting at main() */
int main(int argc, char** argv) {
 glutInit(&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
glutInitWindowSize (500, 500);
glutInitWindowPosition (50, 50);
glutCreateWindow ("Cube");
init();
glutDisplayFunc(display);
glutMainLoop(); // Enter the event-processing loop
 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
}