Category : Pascal Source Code
Archive   : ENGR.ZIP
Filename : NEWDR2.PAS

 
Output of file : NEWDR2.PAS contained in archive : ENGR.ZIP

program newdr; { -> 245 }

var x,x2 : real;
alldone : boolean;
error : boolean;

procedure func(x: real;
var fx,dfx: real);
begin
fx:=x*x-2.0;
dfx:=2.0*x
end; { func }

procedure newton(var x: real);
const tol = 1.0E-6;

var fx,dfx,dx,x1: real;

begin { newton }
repeat
x1:=x;
func(x,fx,dfx);
dx:=fx/dfx;
x:=x1-dx;
writeln('x=',x1,',fx=',fx,',dfx=',dfx);
until abs(dx)<=abs(tol*x)
end; { newton }

begin { main program }
alldone:=false;
repeat
writeln;
write('First guess: '); { first guess }
readln(x);
if x<-19.0 then alldone:=true
else
begin
newton(x);
writeln;
writeln('The solution is ',x);
writeln
end
until alldone
end.