# Cartesian Slope-Intercept Equation

SOURCE CODE :

#### //programed by Paras Wadher MCA Nagpur university

/*program to draw a line using Cartesian Slope-Intercept Equation
[ Simple Implementation ].*/

# include <iostream.h>
# include <graphics.h>
# include <conio.h>
# include <math.h>

void show_screen( );

void slope_intercept_line(const int,const int,const int,const int);

int main( )
{
int driver=VGA;
int mode=VGAHI;

int x_1=0;
int y_1=0;

int x_2=0;
int y_2=0;

do
{
show_screen( );

gotoxy(8,10);
cout<<“Coordinates of Point-I (x1,y1) :”;

gotoxy(8,11);
cout<<“ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ”;

gotoxy(12,13);
cout<<“Enter the value of x1 = “;
cin>>x_1;

gotoxy(12,14);
cout<<“Enter the value of y1 = “;
cin>>y_1;

gotoxy(8,18);
cout<<“Coordinates of Point-II (x2,y2) :”;

gotoxy(8,19);
cout<<“ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ”;

gotoxy(12,21);
cout<<“Enter the value of x2 = “;
cin>>x_2;

gotoxy(12,22);
cout<<“Enter the value of y2 = “;
cin>>y_2;

initgraph(&driver,&mode,”..\\Bgi”);

setcolor(15);
slope_intercept_line(x_1,y_1,x_2,y_2);

setcolor(15);
outtextxy(110,460,”Press <Enter> to continue or any other key to exit.”);

int key=int(getch( ));

if(key!=13)
break;
}
while(1);

return 0;
}

void slope_intercept_line(const int x_1,const int y_1,const int x_2,const int y_2)
{
int color=getcolor( );

float x=x_1;
float y=y_1;

float dx=(x_2-x_1);
float dy=(y_2-y_1);

float m=(dy/dx);
float b=(y-(m*x));

float x_inc=((x_2>=x_1)?1:-1);

putpixel(x,y,color);

while((int)(x+0.5)!=x_2)
{
x+=x_inc;
y=((m*x)+b);

putpixel((int)(x+0.5),(int)(y+0.5),color);
}
}

void show_screen( )
{
restorecrtmode( );
textmode(C4350);

textbackground(1);
cprintf(” Cartesian Slope Intercept Equation “);
textbackground(8);

for(int count=0;count<42;count++)

gotoxy(1,46);

gotoxy(8,40);
cout<<“Note :”;

gotoxy(8,41);
cout<<“ÍÍÍÍÍÍ”;

gotoxy(10,43);
cout<<“This program is better for those lines with é<ñ45ø with x-axis.”;

gotoxy(1,2);
}