point-param.tex

% !TEX encoding = IsoLatin9

%%%%%%%%%%%%%%%%%%%%% SECTION 1
\section{Pointeurs et passage de paramètre}
\begin{frame}
  \begin{columns}
    \column{4.8cm}
    \tableofcontents[currentsection,hideothersubsections]
    \column{7cm}
     
  \end{columns}
  
\end{frame}

\begin{frame}[fragile]
\frametitle{Passage par valeur}

\begin{codeblock}{Argument formel}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
%\lstset{basicstyle=\scriptsize}
\begin{codeC}
int fct (int a);
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

\vspace{2em}

\begin{codeblock}{Argument effectif}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
%\lstset{basicstyle=\scriptsize}
\begin{codeC}
int n = 3 ;
fct(n);
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

\vspace{2em}

\begin{codeblock}{Dans la fonction}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
%\lstset{basicstyle=\scriptsize}
\begin{codeC}
return(a+1);
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

\end{frame}

\begin{frame}[fragile]
\frametitle{Un exemple de passage par valeur}

\begin{columns}
\column{0.6\textwidth}
\begin{codeblock}{}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{codeC}
#include <stdio.h>

void fct(int x)
{
   x = x+2;
}  

int main() 
{
   int a=3;
   fct(a);
   printf("\na=%d",a);
   return (0);
}
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

\column{0.29\textwidth}
\begin{termblock}{Test d'exécution}
%\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{lstlisting}
a=...
\end{lstlisting}
\vspace{-.3cm}
\end{termblock}


\end{columns}

\end{frame}

\begin{frame}[fragile,t]
\frametitle{Suivi de la mémoire}

\begin{columns}[t]

%%%%% COL1 %%%%%%%%%%
\column{0.22\textwidth}
\vspace{1.3em}
\begin{codeblock}{}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{codeC}
int main() 
{
  int a=3;
  fct(a);§\tmark{c1}§
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

\vspace{4.2em}

\begin{codeblock}{}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{codeC}
  printf("a=%d"§\tmark{c4}§
   ,a);
  return (0);
}
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

%%%% COL2 %%%%
\column{0.18\textwidth}
\centering
\textcolor{blue}{Contexte du \Verb|main|}
\begin{block}{}
\vspace{-0.5em}
\centering
\begin{tabular}{|c|}
\multicolumn{1}{c}{\Verb|a|}\\
\hline
\textcolor{gray}{1201}\\
\hline
3\tmark{ma}\\
\hline
\end{tabular}
\end{block}

%%%% COL3 %%%%%
\column{0.24\textwidth}

\vspace{5em}

\begin{codeblock}{}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{codeC}
§\tmark{c2}§void fct(int x)
{
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

\vspace{1.3em}

\begin{codeblock}{}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{codeC}
 x = x + 2 ;
§\tmark{c3}§}
\end{codeC}
\vspace{-.3cm}
\end{codeblock}


%%% COL4 %%%%
\column{0.18\textwidth}
\textcolor{teal}{Contexte de \Verb|fct|}

\vspace{2.8em}

\begin{exampleblock}{}
\vspace{-0.5em}
\centering
\begin{tabular}{|c|}
\multicolumn{1}{c}{\Verb|x|}\\
\hline
\textcolor{gray}{1202}\\
\hline
\tmark{fx}3\\
\hline
\end{tabular}
\end{exampleblock}

\begin{exampleblock}{}
\vspace{-0.5em}
\centering
\begin{tabular}{|c|}
\multicolumn{1}{c}{\Verb|x|}\\
\hline
\textcolor{gray}{1202}\\
\hline
5\\
\hline
\end{tabular}
\end{exampleblock}


\end{columns}

\begin{tikzpicture}[remember picture,overlay, auto,
 cline/.style     = { draw, color=red, ->},
 pline/.style     = { draw, very thick, color=teal, ->},
]
\begin{scope} [every path/.style=cline]
\path (c1) -- (c2) ;
\path (c3) -- (c4) ;
\end{scope}

\draw[color=teal, very thick] (ma) edge[bend left=45, ->,shorten >=3pt] 
node[midway, above]{3} (fx) ;

\end{tikzpicture}

\end{frame}

\begin{frame}[fragile]
\frametitle{Passage par adresse (ou par référence)}

\begin{codeblock}{Argument formel}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
%\lstset{basicstyle=\scriptsize}
\begin{codeC}
int fct (int *pa);
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

\vspace{2em}

\begin{codeblock}{Argument effectif}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
%\lstset{basicstyle=\scriptsize}
\begin{codeC}
int n = 3 ;
fct(&n);
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

\vspace{2em}

\begin{codeblock}{Dans la fonction}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
%\lstset{basicstyle=\scriptsize}
\begin{codeC}
return(*pa + 1);
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

\end{frame}

\begin{frame}[fragile]
\frametitle{Un exemple de passage par adresse}

\begin{columns}
\column{0.6\textwidth}
\begin{codeblock}{}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{codeC}
#include <stdio.h>

void fct(int *px)
{
   *px = *px+2;
}  

int main() 
{
   int a=3;
   fct(&a);
   printf("\na=%d",a);
   return (0);
}
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

\column{0.29\textwidth}
\begin{termblock}{Test d'exécution}
%\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{lstlisting}
a=...
\end{lstlisting}
\vspace{-.3cm}
\end{termblock}


\end{columns}

\end{frame}


\begin{frame}[fragile,t]
\frametitle{Suivi de la mémoire}

\begin{columns}[t]

%%%%% COL1 %%%%%%%%%%
\column{0.22\textwidth}
\vspace{1.3em}
\begin{codeblock}{}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{codeC}
int main() 
{
  int a=3;
  fct(&a);§\tmark{c1}§
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

\vspace{4.2em}

\begin{codeblock}{}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{codeC}
  printf("a=%d"§\tmark{c4}§
   ,a);
  return (0);
}
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

%%%% COL2 %%%%
\column{0.18\textwidth}
\centering
\textcolor{blue}{Contexte du \Verb|main|}
\begin{block}{}
\vspace{-0.5em}
\centering
\begin{tabular}{|c|}
\multicolumn{1}{c}{\Verb|a|}\\
\hline
\textcolor{gray}{1201}\tmark{ma}\\
\hline
3\\
\hline
\end{tabular}
\end{block}

\begin{block}{}
\vspace{-0.5em}
\centering
\begin{tabular}{|c|}
\multicolumn{1}{c}{\Verb|a|}\\
\hline
\textcolor{gray}{1201}\\
\hline
5\tmark{mp}\\
\hline
\end{tabular}
\end{block}

%%%% COL3 %%%%%
\column{0.24\textwidth}

\vspace{5em}

\begin{codeblock}{}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{codeC}
§\tmark{c2}§void fct(int *px)
{
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

\vspace{1.3em}

\begin{codeblock}{}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{codeC}
 *px = *px + 2 ;
§\tmark{c3}§}
\end{codeC}
\vspace{-.3cm}
\end{codeblock}


%%% COL4 %%%%
\column{0.18\textwidth}
\textcolor{teal}{Contexte de \Verb|fct|}

\vspace{2.8em}

\begin{exampleblock}{}
\vspace{-0.5em}
\centering
\begin{tabular}{|c|}
\multicolumn{1}{c}{\Verb|px|}\\
\hline
\textcolor{gray}{1202}\\
\hline
\tmark{fx}1201\\
\hline
\end{tabular}
\end{exampleblock}

\begin{exampleblock}{}
\vspace{-0.5em}
\centering
\begin{tabular}{|c|}
\multicolumn{1}{c}{\Verb|px|}\\
\hline
\textcolor{gray}{1202}\\
\hline
\tmark{fp}1201\\
\hline
\end{tabular}
\end{exampleblock}


\end{columns}

\begin{tikzpicture}[remember picture,overlay, auto,
 cline/.style     = { draw, color=red, ->},
 pline/.style     = { draw, very thick, color=teal, ->},
]
\begin{scope} [every path/.style=cline]
\path (c1) -- (c2) ;
\path (c3) -- (c4) ;
\end{scope}

\draw[color=teal, very thick] (ma) edge[bend left=45, ->,shorten >=3pt] 
node[midway, above]{1201} (fx) ;
\draw (fp) edge [dashed, bend right, ->, shorten >=3pt] node[midway, above]{*px} (mp) ;

\end{tikzpicture}

\end{frame}

\begin{frame}[fragile]
\frametitle{Passage par valeur Vs adresse}
\begin{columns}
\column{0.45\textwidth}
\begin{codeblock}{}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{codeC}
include <stdio.h>
int fonction(int x)
{
  int a=2;
  printf("\n2)a=%d,x=%d",a,x);
  x += a;
  printf("\n3)a=%d,x=%d",a,x);
  return (x);
}
int main()
{
  int a=0, x=4;
  printf("\n1)a=%d,x=%d",a,x);
  a = fonction(x);
  printf("\n4)a=%d,x=%d",a,x);
  return(0);
}
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

\begin{Verbatim}
1) a=..., x=...
2) a=..., x=...
3) a=..., x=...
4) a=..., x=...
\end{Verbatim}

\column{0.48\textwidth}
\begin{codeblock}{}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{codeC}
include <stdio.h>
int fonction(int *px)
{
 int a=2;
 printf("\n2)a=%d,*px=%d",a,*px);
 *px += a;
 printf("\n3)a=%d,*px=%d",a,*px);
 return (*px);
}
int main()
{
 int a=0, x=4;
 printf("\n1)a=%d,x=%d",a,x);
 a = fonction(&x);
 printf("\n4)a=%d,x=%d",a,x);
 return(0);
}
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

\begin{Verbatim}
1) a=..., x=...
2) a=..., *px=...
3) a=..., *px=...
4) a=..., x=...
\end{Verbatim}

\end{columns}
\end{frame}



\begin{frame}[fragile]
\frametitle{Exemple : échange du contenu de 2 variables}

\begin{columns}
\column{0.6\textwidth}
\begin{codeblock}{}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{codeC}
#include <stdio.h>
void echange(int * x, int * y)
{
   int tmp = *x;
   *x = *y;
   *y = tmp;
}
void main()
{
   int a=4, b=5;
   printf("\n1) a= %d, b=%d",a,b);
   echange(&a,&b);
   printf("\n2) a= %d, x=%d",a,b);
   return (0);
}
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

\column{0.29\textwidth}
\begin{termblock}{Test d'exécution}
%\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{lstlisting}
1) a=..., b=...
2) a=..., b=...
\end{lstlisting}
\vspace{-.3cm}
\end{termblock}


\end{columns}

\end{frame}

\begin{frame}[fragile]
\frametitle{Ça explique}
\begin{itemize}
\setlength\itemsep{1em}
\item L'utilisation du \bvrb|&| dans le \bvrb|scanf|
\begin{columns}
\column{0.3\textwidth}
\begin{codeblock}{}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{codeC}
scanf("%d",&n) ;
\end{codeC}
\vspace{-.3cm}
\end{codeblock}
\column{0.4\textwidth}
\Verb|&n| est une adresse
\end{columns}

\item Le statut particulier des chaînes de caractères dans \bvrb|scanf|
\begin{columns}
\column{0.3\textwidth}
\begin{codeblock}{}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{codeC}
char chaine[50];
scanf("%s",chaine);
\end{codeC}
\vspace{-.3cm}
\end{codeblock}
\end{columns}
\Verb|chaine| est un tableau de caractères, c'est à dire
un pointeur (donc il contient déjà une adresse).

\item Le fait que les tableaux passés en argument des fonctions
étaient modifiés.

\end{itemize}
\begin{columns}
\column{0.4\textwidth}
\begin{codeblock}{}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{codeC}
void init (int *Tab);
\end{codeC}
\vspace{-.3cm}
\end{codeblock}

\column{0.4\textwidth}
\begin{codeblock}{}
\vspace{-.3cm}
\lstset{escapeinside={§§}}
\lstset{basicstyle=\scriptsize}
\begin{codeC}
void init (int Tab[]);
\end{codeC}
\vspace{-.3cm}
\end{codeblock}
\end{columns}

\end{frame}