dda grapg

/*program to draw a graph of rainfall acording to % for 5 years*/
#include<stdio.h>
#include<conio.h>
#include<graphics.h>
#include<math.h>

void drawline(int,int,int,int,int);
void main()
{
    int gd=0,gm,i;
    int x,y,data1,data2,data3,data4,data5;
    int blue=1,red=4,green=2,magneta=5,cyan=3,white=15;
    initgraph(&gd,&gm,"C:\\TC\\BGI");
    x=getmaxx();            //getting max resolution
    y=getmaxy();
    printf("\nENTER THE RAINFALL  DATA FOR YEAR 2010 : ");      //accepting data from user
    scanf("%d",&data1);
    printf("ENTER THE RAINFALL  DATA FOR YEAR 2011 : ");
    scanf("%d",&data2);
    printf("ENTER THE RAINFALL  DATA FOR YEAR 2012 : ");
    scanf("%d",&data3);
    printf("ENTER THE RAINFALL  DATA FOR YEAR 2013 : ");
    scanf("%d",&data4);
    printf("ENTER THE RAINFALL DATA FOR YEAR 2014 : ");
    scanf("%d",&data5);
    drawline(0,y/2+200,x,y/2+200,white);            //drawing x and y axes
    drawline(x/2-250,0,x/2-250,y,white);

    //bar 1
    for(i=200;i<=220;i++)
    {
        drawline(x/2-i,y-40,x/2-i,y-40-data1,blue);
    }

    //bar 2
    for(i=150;i<=170;i++)
    {
        drawline(x/2-i,y-40,x/2-i,y-40-data2,green);
    }

    //bar 3
    for(i=100;i<=120;i++)
    {
        drawline(x/2-i,y-40,x/2-i,y-40-data3,cyan);
    }

    //bar 4
    for(i=50;i<=70;i++)
    {
        drawline(x/2-i,y-40,x/2-i,y-40-data4,red);
    }

    //bar 5
    for(i=0;i<=20;i++)
    {
        drawline(x/2-i,y-40,x/2-i,y-40-data5,magneta);
    }
    getch();
}

void drawline (int xa,int ya,int xb,int yb,int color)
{
  int i=0;
  //int xorigin,yorigin;
  float x1,y1,dx,dy,length,x,y,xinr,yinr;
  //xorigin=getmaxx();
  //yorigin=getmaxy();
  if(abs(xb-xa) > abs(yb-ya))  //step 2 calculate lenght,dx,dy
  {
        length=abs(xb-xa);
  }
  else
  {
        length=abs(yb-ya);
  }
  dx=(xb-xa)/length;
  dy=(yb-ya)/length;
  putpixel(xa,ya,color);        //step 3 print first pixel
  x1=xa;
  y1=ya;
  for(i=0;i<length;i++)         //step 4 print the next pixels by incrementing
  {
        x1=x1+dx;
        y1=y1+dy;
        putpixel(x1+0.5,y1+0.5,color);
  }
  return;
}