28
clearscreen
(cs)
erase the graphics screen, returns the turtle to the centre
of the screen, and sets the turtle’s heading to
0. CLEARSCREEN does not affect the pen state or
screen colours.
xcor
output the X coordinate of the turtle.
ycor
output the Y coordinate of the turtle.
heading
output the turtle’s degree.
turtlestate
(ts)
output 4 turtle properties:
pen down?
turtle visible?
background colour
pen colour
wrap
make the turtle remain inside the graphics window
no matter how large a movement command is given.
Any time the turtle moves off the window borders, it
wraps around the window and reappears on the opposite
edge.
window
remove the boundaries from the turtle’s field of movement.
If the turtle moves beyond the borders of the graphics
window, it continues to move, but cannot be seen.
fence
prevent the turtle from moving beyond the edge of
the graphics window. If you try to move the turtle off
the window, it does not move and Logo displays a
message.
2. Mathematics Commands
abs
n
output the absolute value of its input.
arctan
n
output the arctangent of its input.
cos
n
output the cosine of its input.
expn
n
calculate the natural base e (2.71828. . .) raised to
the power specified by its input.
int
n
output the integer portion of its input by removing
the decimal portion, if any. No rounding occurs.
log
n
output the natural logarithm of its input.
log10
n
output the base 10 logarithm of its input.
product
m n
output the product of its inputs. PRODUCT expects
two inputs, but will accept more if it and all its inputs
are enclosed in parentheses.
quotient
m n
output the result of dividing the first input by the second
input.
random
n
output a randomly selected number from 1 through
its input.
34600 I/M
2/28/00, 11:27 AM
28
Содержание Power Zone Edge
Страница 1: ......