\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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