Inaccurate results from Lagrange Interpolation in Fortran - fortran

Question

I have written a Fortran program to compute the Lagrange interpolation of two data sets: x,G. I am not able to evaluate the defined function correctly. Please see what I did wrong as while my program runs, the numbers are not at all accurate for the fxn see first two programs (Matlab code) to see actual result). They are provided by the author and are what I am trying to emulate on Fortran:
%% example 1.1 langrange interpolation %(Matlab)
% X : interpolation points
% Y : value of f(X)
% x : points where we want an evaluation of P(x),
% where P is the interpolator polynomial
x = [-1:0.01:1];
X = [-1:0.20:1];
y = 1./(1+25*x.^2);
Y = 1./(1+25*X.^2);
pol = lagrange_interp(X,Y,x)
%plot(x,pol,'k',x,y,'k--',X,Y,'k.');
legend('Lagrange Polynomial','Expected behavior','Data Points');
function polynomial = lagrange_interp(X,Y,x) %(Matlab)
n = length(X);
phi = ones(n,length(x));
polynomial = zeros(1,length(x));
i = 0;
j = 0;
for i = [1:n]
for j = [1:n]
if not(i==j)
phi(i,:) = phi(i,:).*(x-X(j))./(X(i)-X(j));
end;
end;
end;
for i = [1:n]
polynomial = polynomial + Y(i)*phi(i,:);
end;
!Lagrange Interpolation example !(Fortran)
program Lagrange
implicit none
integer:: i
integer, parameter:: n=10
integer, parameter:: z=201
integer, parameter:: z1=11
real, parameter:: delta=.01
real,parameter:: delta2=.20
real, dimension(1:z):: x,G,y,H
real*8, dimension(1:n):: M
real*8, dimension(1:n):: linterp(n)
x(1)=-1
G(1)=-1
do i=2,z
x(i)=x(i-1)+delta
y(i)=1/(1+25*(x(i)**2))
end do
print*, "The one-dimensional array x is:", x(1:z)
print*, "The one dimensional array y is", y(1:z)
do i=2,z1
G(i)=G(i-1)+delta2
H(i)=1/(1+25*(G(i)**2))
end do
print*,"The other one-dimensional array G is:", G(1:z1)
print*, "Then the one dimensional array H is", H(1:z1)
M=linterp(1:n)
print*, M(1:n)
end program
!Lagrange interpolation polynomial function !(Fortran)
real*8 function linterp(n)
implicit none
integer,parameter:: n=10
integer, dimension(1:n):: poly,pol
integer:: i, j
i=0
j=0
do i=1,n
do j=1,n
if (i/=j)then
poly(i,j)=poly(i,j)*(x(i)-G(j))/(y(i)-G(j))
end if
end do
end do
print*, poly(i,j)
do i=1,n
pol(i)=pol(i)+H(i)*poly(i,j)
end do
print*, pol(1:n)
end function