program exponential
c This program adds terms of the Taylor series for exp(x).
c The user inputs the x value and the desired number of terms.
real x, sum, term
integer i, n
character ans*1
5 print *, "For what x-value do you want to sum the series?"
read *, x
print *, "At what n do you want to stop the sum?"
read *, n
sum = 1
term = 1
do i = 1, n
term = term * x / i
sum = sum + term
end do
print *, "The Taylor approximation of order", n
print *, "of exp x at x =", x, " is", sum
print *, "The actual value of exp", x, " is", exp(x)
print *, "Do you want to repeat (y or n) ?"
read *, ans
if (ans .eq. "y" .or. ans .eq. "Y") goto 5
print *, "Sayonara"
end