#include<stdio.h>
#include<graphics.h>
#include<math.h>
void bline(float x1,float y1,float x2,float y2);
void main()
{
    int gd=DETECT,gm;
    float wy,wx,x1,y1,x2,y2;
    int i,thickness;
    initgraph(&gd,&gm,"");
    printf("Enter x1,y1,x2,y2:\n");
    scanf("%f%f%f%f",&x1,&y1,&x2,&y2);
    printf("\nEnter thickness of line: ");
    scanf("%d",&thickness);
    bline(x1,y1,x2,y2);
    if((y2-y1)/(x2-x1)<1)
    {
        wy=(thickness-1)*sqrt(pow((x2-x1),2)+pow((y2-y1),2))/(2*fabs(x2-x1));
        for(i=0;i<wy;i++)
        {
            bline(x1,y1-i,x2,y2-i);
            bline(x1,y1+i,x2,y2+i);
        }
    }
     else
    {
        wx=(thickness-1)*sqrt(pow((x2-x1),2)+pow((y2-y1),2))/(2*fabs(y2-y1));
        for(i=0;i<wx;i++)
        {
            bline(x1-i,y1,x2-i,y2);
            bline(x1+i,y1,x2+i,y2);
        }
    }
     getch();
    closegraph();
    restorecrtmode();
}
void bline(float x1,float y1,float x2,float y2)
{
    float xinc,yinc,x,y;
    float dx,dy,e;
    dx=abs(x2-x1);
    dy=abs(y2-y1);
    if(x1<x2)
        xinc=1;
    else
        xinc=-1;
    if(y1<y2)
        yinc=1;
    else
        yinc=-1;
    x=x1;
    y=y1;
     putpixel(x,y,WHITE);
    if(dx>=dy)
    {
       e=(2*dy)-dx;
       while(x!=x2)
       {
           if(e<0)
           {
               e+=(2*dy);
           }
           else
           {
               e+=(2*(dy-dx));
               y+=yinc;
           }
           x+=xinc;
           putpixel(x,y,WHITE);
        }
    }
    else
    {
        e=(2*dx)-dy;
        while(y!=y2)
        {
            if(e<0)
            {
                e+=(2*dx);
            }
            else
            {
                e+=(2*(dx-dy));
                x+=xinc;
            }
            y+=yinc;
            putpixel(x,y,WHITE);
        }
    }
}
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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
}