Version 5.0 The LEDA User Manual

int W.read int(string p) displays a panel with prompt p for integer input, returns
the input.
3.7 Input and output operators
For input and output of basic geometric objects in the plane such as points, lines, line segments,
circles, and polygons the > operators can be used. Similar to C++input
streams windows have an internal state indicating whether there is more input to read or
not. Its initial value is true and it is turned to false if an input sequence is terminated by
clicking the right mouse button (similar to ending stream input by the eof character). In
conditional statements, objects of type window are automatically converted to boolean
by returning this internal state. Thus, they can be used in conditional statements in the
same way as C++input streams. For example, to read a sequence of points terminated by
a right button click, use “ while (W >> p) { . . . } ”.
3.7.1 Output
window& W ≪ const point& p like W .draw point(p).
window&
W ≪ const segment& s
like W .draw segment(s).
window& W ≪ const ray& r like W .draw ray(r).
window& W ≪ const line& l like W .draw line(l).
window&
window&
window&
window&
window&
W ≪ const circle& C like W .draw circle(C).
W ≪ const polygon& P
like W .draw polygon(P ).
W ≪ const gen polygon& P
like W .draw polygon(P ).
W ≪ const rectangle& R
like W .draw rectangle(R).
W ≪ const triangle& T
like W .draw triangle(T ).
3.7.2 Input
window& W ≫ point& p reads a point p: clicking the left button assigns the
current cursor position to p.