\input LEDA.mac

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{\magtwobf Changes with respect to version 2.0 \bigskip

{\magonebf 1.6 Input and output \bigskip

The overloaded $Read$ and $Write$ functions for defining input and output functions for user defined pointer types now have an additional stream argument.

$void$\ \ $Read(T\&,\ istream\&)$ $\{$ \dots $\$\nl defines an input function for reading objects of type $T$ from an input stream.

$void$\ \ $Print(T\&,\ ostream\&)$ $\{$ \dots $\$ \nl defines an output function for printing objects of type $T$ to an output stream.

\+\cleartabs & \hskip 2truecm & \hskip 5.5truecm &\cr

\bigskip {\magonebf 3.1 One Dimensional Arrays (array) \bigskip \def\var {$A$ \+\op void sort {int\ (*cmp)(E\&, E\&),\ int\ l,\ int\ h { \+\nop {applies the sorting operation to the sub-array \+\nop {\var$[l..h]$. \medskip \+\op void read {istream\ I {reads $b-a+1$ objects of type $E$ from the input \+\nop {stream $I$ into the array $A$ using the overloaded \+\nop {$Read$ function (section 1.6) \smallskip \+\op void read { {Calls $A$.read($cin$) to read $A$ from \+\nop {the standard input stream $cin$. \smallskip \+\op void read {string\ s {As above, but uses string $s$ as a prompt. \smallskip \+\op void print {ostream\ O,\ char\ space = ’\ ’ { \+\nop {Prints the contents of array $A$ to the output \+\nop {stream $O$ using the overload $Print$ function \+\nop {(section 1.5) to print each element. The elements \+\nop {are separated by the space character $space$. \smallskip \+\op void print {char\ space = ’\ ’ {Calls $A$.print($cout$, $space$) to print $A$ on \+\nop {the standard output stream $cout$. \smallskip \+\op void print {string\ s,\ char\ space = ’\ ’ { \+\nop {As above, but uses string $s$ as a header.

\vfill\eject

\bigskip {\magonebf 3.7 Linear Lists (list) \bigskip \def\var {$L$ \+\op void read {istream\ I,\ char\ delim = ’\backslash n’ { \+\nop {reads a sequence of objects of type $E$ terminated \+\nop {by the delimiter $delim$ from the input stream $I$ \+\nop {using the overloaded $Read$ function (section 1.5) \+\nop {$L$ is made a list of appropriate length and the \+\nop {sequence is stored in $L$. \smallskip \+\op void read {char\ delim = ’\backslash n’ {Calls $L$.read($cin$, $delim$) to read $L$ from \+\nop {the standard input stream $cin$. \smallskip \+\op void read {string\ s,\ char\ delim = ’\backslash n’ { \+\nop {As above, but uses string $s$ as a prompt. \smallskip \+\op void print {ostream\ O,\ char\ space = ’\ ’ { \+\nop {Prints the contents of list $L$ to the output \+\nop {stream $O$ using the overload $Print$ function \+\nop {(section 1.5) to print each element. The elements \+\nop {are separated by the space character $space$. \smallskip \+\op void print {char\ space = ’\ ’ {Calls $L$.print($cout$, $space$) to print $L$ on \+\nop {the standard output stream $cout$. \smallskip \+\op void print {string\ s,\ char\ space = ’\ ’ { \+\nop {As above, but uses string $s$ as a header.

\bigskip {\magonebf 5.4 Parameterized Graphs (GRAPH) \bigskip \def\var {$G$ \+\op void write {string\ fname {writes $G$ to the file with name $fname$. The \+\nop {overloaded functions $Print(vtype,ostream)$ \+\nop {and $Print(etype,ostream)$ (cf. section 1.6) \+\nop {are used to write the node and edge entries \+\nop {of $G$ respectively. \smallskip \+\op int read {string\ fname {reads $G$ from the file with name $fname$. The \+\nop {overloaded functions $Read(vtype,istream)$ \+\nop {and $Read(etype,istream)$ (cf. section 1.6) \+\nop {are used to read the node and edge entries \+\nop {of $G$ respectively. Returns error code \+\nop {1 \quad if file $fname$ does not exist \+\nop {2 \quad if graph is not of type $GRAPH(vtype,etype)$ \+\nop {3 \quad if file $fname$ does not contain a graph \+\nop {0 \quad otherwise.

\vfill\eject

\bigskip {\magonebf 6.3 Sets of two-dimensional points (point\_set) \bigskip \def\var {$S$ \+\cleartabs & \hskip 3truecm & \hskip 4.5truecm &\cr \+\op list(ps\_item) convex\_hull { { \+\nop {returns the list of items containing \+\nop {all points of the convex hull of \var \+\nop {in clockwise order.

\bigskip {\magonebf 6.1.6 Plane Algorithms \bigskip

$\bullet$ {\bf Voronoi Diagrams

$void$\quad VORONOI$(list(point)\& \ sites,\ real\ R,\ GRAPH(point,point)\&\ G)$

VORONOI takes as input a list of points $sites$ and a real number $R$. It computes a directed graph $G$ representing the planar subdivision defined by the Voronoi-diagram of $sites$ where all “infinite" edges have length $R$. For each node $v$ $G$.inf($v$) is the corresponding Voronoi vertex ($point$) and for each edge $e$ $G$.inf($e$) is the site ($point$) whose Voronoi region is bounded by $e$.

\bigskip {\magonebf 6.7 Graphic Windows (window)

Data type $gwindow$ no longer exists, it is replaced by data type $window$

The data type $window$ provides an interface for the input and output of basic two-dimensinal geometric objects (cf. section 5.1) using the X11 (xview) or SunView window system. There are two object code libraries (libWs.a, libWx.a) containing implementations for different environments. Application programs using data type $window$ have to be linked with one of these libraries (cf. section~1.6):

\beginitem \item{ a) For the SunView window system:\nl CC $prog.c$ -lWs -lP -lG -lL -lm -lsuntool -lsunwindow -lpixrect

\item{ b) For the X11 (open windows) window system:\nl CC $prog.c$ -lWx -lP -lG -lL -lm -lxview -lolgx -lX11

\enditem

\vfill\eject

{\bf Creation of a graphic window \bigskip \cleartabs \bigskip \+a) &$window$ $W(int\ xpix,\ int\ ypix,\ int\ xpos,\ int\ ypos)$;\cr \bigskip \+b) &$window$ $W(int\ xpix,\ int\ ypix)$;\cr \bigskip \+c) &$window$ $W()$;\cr \bigskip

Variant a) creates a window $W$ of physical size $xpix \times ypix$ pixels with its upper left corner at position ($xpos,ypos$) on the screen, variant b) places $W$ into the upper right corner of the screen, and variant c) creates a $850 \times 850$ pixel window positioned into the upper right corner.

All three variants initialize the coordinates of $W$ to $x0 = 0$, $x1 = 100$ and $y0 = 0$. The $init$ operation (see below) can later be used to change the window coordinates and scaling.

{\bf Additional operations:

\bigskip \bigskip \def\var {$W$ \+\op int read\_panel {string\ h,\ int\ n,\ string*\ S { \+\nop {displays a panel with header $h$ and an array $S[1..n]$ \+\nop {of $n$ string items, returns the index of the selected \+\nop {item. \medskip \+\op int read\_vpanel {string\ h,\ int\ n,\ string*\ S { \+\nop {like read\_panel with vertical button layout \medskip \+\op int read\_int {string\ p { \+\nop {displays a panel with prompt $p$ for integer input, \+\nop {returns the input \medskip \+\op real read\_real {string\ p { \+\nop {displays a panel with prompt $p$ for real input \+\nop {returns the input \medskip \+\op string read\_string {string\ p { \+\nop {displays a panel with prompt $p$ for string input, \+\nop {returns the input \medskip \+\op string read\_string {string\ p,\ list(string)\ menu { \+\nop {as above, adds an additional menu button which \+\nop {can be used to select a string from $menu$. \medskip \+\op string read\_string {string\ p,\ string\ label,\ list(string)\ menu { \+\nop {as above, the menu button is labelled with $label$. \medskip

\vfill\eject

{\magonebf 7.1 Streams

The stream data types described in this section are all derived from the \CC stream types $istream$ and $ostream$. Some of these types may be obsolete in combination with some of the latest versions of the standard \CC I/O library.

\bigskip {\magonebf 7.1.3 String input streams (string\_istream)

An instance $I$ of the data type $string\_istream$ is an \CC istream connected to a string $s$, i.e., all input operations or operators applied to $I$ read from $s$.

{\bf 1. Creation of a string input stream

$string\_istream\ \ \ I(string\ s)$;

creates an instance $I$ of type string\_istream connected to the string $s$.

{\bf 2. Operations

All operations and operators ($>>$) defined for \CC istreams can be applied to string input streams as well.

\bigskip {\magonebf 7.1.4 String output streams (string\_ostream)

An instance $O$ of the data type $string\_ostream$ is an \CC ostream connected to an internal string buffer, i.e., all output operations or operators applied to $O$ write into this internal buffer. The current value of the buffer is called the contents of $O$.

{\bf 1. Creation of a string output stream

$string\_ostream\ \ \ O$;

creates an instance $O$ of type string\_ostream.

{\bf 2. Operations \medskip \cleartabs \+\hskip 1.8truecm &\hskip 5truecm &\cr \medskip \+string &O.clear() &clears the contents of $O$\cr \medskip \+string &O.str() &returns the current contents of $O$\cr \smallskip

All operations and operators ($<<$) defined for \CC ostreams can be applied to string output streams as well.

\bigskip {\magonebf 7.1.5 Command input streams (cmd\_istream)

An instance $I$ of the data type $cmd\_istream$ is an \CC istream connected to the output of a shell command $cmd$, i.e., all input operations or operators applied to $I$ read from the standard output of command $cmd$.

{\bf 1. Creation of a command input stream

$cmd\_istream\ \ \ in(string\ cmd)$;

creates an instance $in$ of type cmd\_istream connected to the output of command $cmd$.

{\bf 2. Operations

All operations and operators ($>>$) defined for \CC istreams can be applied to command input streams as well.

\bigskip {\magonebf 7.1.6 Command output streams (cmd\_ostream)

An instance $O$ of the data type $cmd\_ostream$ is an \CC ostream connected to the input of a shell command $cmd$, i.e., all output operations or operators applied to $O$ write into the standard input of command $cmd$.

{\bf 1. Creation of a command output stream

$cmd\_ostream\ \ \ out(string\ cmd)$;

creates an instance $out$ of type cmd\_ostream connected to the input of command $cmd$.

{\bf 2. Operations

All operations and operators ($<<$) defined for \CC ostreams can be applied to command output streams as well.

\vfill\eject \bye

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