Circle Through Three Points

Program In C Language for Circle Through Three Points

#include < stdio.h>
#include < math.h>
#include < conio.h>

int main()
{
clrscr();
double f,g,m,x1,x2,x3,y1,y2,y3;
double c,d,h,e,k,r,s;
for(;;)
{
if(scanf("%lf %lf %lf %lf %lf %lf",&x1,&y1,&x2,&y2,&x3,&y3)==EOF)
//checking for input
break;

f = x3*x3-x3*x2-x1*x3+x1*x2+y3*y3-y3*y2-y1*y3+y1*y2; //formula
g = x3*y1-x3*y2+x1*y2-x1*y3+x2*y3-x2*y1;

if(g==0)
m = 0;
else
m = (f/g);

c = (m*y2)-x2-x1-(m*y1); //formula
d = (m*x1)-y1-y2-(x2*m);
e = (x1*x2)+(y1*y2)-(m*x1*y2)+(m*x2*y1);

h = (c/2); //formula
k = (d/2);
s = (((h)*(h))+((k)*(k))-e);
r = pow(s,.5);

printf("(x");

if(h>=0)
printf(" + ");
else if(h< 0)
printf(" - ");
if(h< 0)
h=-h;
printf("%.3lf)^2",(h));
printf(" + ");
printf("(y");
if(k>=0)
printf(" + ");
else if(k< 0)
printf(" - ");
if(k< 0)
k=-k;
printf("%.3lf)^2 = %.3lf^2",(k),r);

printf("");

printf("x^2 + y^2");

if(c>=0) printf(" + ");
else if(c< 0) printf(" - ");

if(c< 0) c=-c;
printf("%.3lfx",c);

if(d>=0) printf(" + ");
else if(d< 0) printf(" - ");

if(d< 0) d=-d;
printf("%.3lfy",d);

if(e>=0) printf(" + ");
else if(e< 0) printf(" - ");

if(e< 0) e=-e;
printf("%.3lf = 0",e);
printf("");
}

getch();
return 0;
}

Decimal To Roman Conversion

/* Program in C for Decimal to Roman Number conversion */

#include< stdio.h>

main()
{
int a,b,c,d,e;
clrscr();
printf("Input a number (between 1-3000):");
scanf("%d",&e);
while (e==0||e>3000)
{
printf ("ERROR: Invalid Input!
");
printf ("Enter the number again:");
scanf ("%d",&e);
}
if (e>3000)
printf("Invalid");
a = (e/1000)*1000;
b = ((e/100)%10)*100;
c = ((e/10)%10)*10;
d = ((e/1)%10)*1;

if (a ==1000)
printf("M");
else if (a ==2000)
printf("MM");
else if (a ==3000)
printf("MMM");

if (b == 100)
printf("C");
else if (b == 200)
printf("CC");
else if (b == 300)
printf("CCC");
else if (b == 400)
printf("CD");
else if (b ==500)
printf("D");
else if (b == 600)
printf("DC");
else if (b == 700)
printf("DCC");
else if (b ==800)
printf("DCCC");
else if (b == 900)
printf("CM");


if (c == 10)
printf("X");
else if (c == 20)
printf("XX");
else if (c == 30)
printf("XXX");
else if (c == 40)
printf("XL");
else if (c ==50)
printf("L");
else if (c == 60)
printf("LX");
else if (c == 70)
printf("LXX");
else if (c ==80)
printf("LXXX");
else if (c == 90)
printf("XC");

if (d == 1)
printf("I");
else if (d == 2)
printf("II");
else if (d == 3)
printf("III");
else if (d == 4)
printf("IV");
else if (d ==5)
printf("V");
else if (d == 6)
printf("VI");
else if (d == 7)
printf("VII");
else if (d ==8)
printf("VIII");
else if (d == 9)
printf("IX");
getch();
}