Question: i'm studing fortran programation through the cambridge self-study guide 2. In the page 11 we can find this program:

```
program projectile
implicit none

! define constants
real, parameter :: g = 9.8
real, parameter :: pi = 3.1415927
real :: a, t, u, x, y
real :: theta, v, vx, vy

! Read values for a, t, and u from terminal
read(*,*) a, t, u

! convert angle to radians
a = a * pi / 180.0
x = u * cos(a) * t
y = u * sin(a) * t – 0.5 * g * t * t
vx = u * cos(a)
vy = u * sin(a) - g * t
v = sqrt(vx * vx + vy * vy)
theta = atan(vy / vx) * 180.0 / pi

write(*,*) 'x: ',x,'y: ',y
write(*,*) 'v: ',v,'theta: ',theta

end program projectile

```

But it generates an "Unclassificable statement at (1)" in line 16, can someone please help me? thx

Answer: 
Oh this takes me back. I took this course too when I was a lot younger!

I don't know how you managed to type this, but what appears to be the subtraction operator in 

`y = u * sin(a) * t – 0.5 * g * t * t`

has been written with the wrong symbol. You need to use -, not the en-dash. Did you copy the formula straight from a lecture document?

Also, if you don't mind my saying so, your definition of `g` has an inadequate amount of precision cf. your other variables.
In your line

```
y = u * sin(a) * t – 0.5 * g * t * t

```

you have a character that looks like MINUS SIGN (`-`) but isn't - it's an EN DASH (`–`). Yes, they look almost the same. No, you can't use one instead of the other.