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\author{Piyush P Kurur\\
  Office no: 224\\
  Dept. of Comp. Sci. and Engg.\\
  IIT Kanpur}


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\title{Fundamentals of Computing: Lecture 16}
\date{September 4, 2009}
\begin{document}
\begin{frame}
  \maketitle
\end{frame}

\begin{frame}
  \frametitle{Summary of the previous lecture}

  \begin{itemize}
  \item Integers can be added and subtracted to pointers.
  \item Difference of two pointers can be taken if they are of the
    same type.
  \item The operator |ptr++| etc also works.
    array.
  \end{itemize} 
    
\end{frame}

\begin{frame}
  \frametitle{Summary continued...}
  \begin{itemize}
  \item For arrays |T a[100]| the value |a| is the
    address of the starting element.
  \item The expression |&a[i]| is equivalent to |a+i|
  \item The expression |a[i]| is equivalent to |*(a+i)|.
  \end{itemize}
\end{frame}
\begin{frame}

\frametitle{Passing arrays to functions}
  
\begin{itemize}
\item The value of an array variable is the starting address.
\item Functions are call by value.
\end{itemize}
\end{frame}
\begin{frame}
  \begin{code}
    #include <stdio.h>
    
    int strlen(char *ptr)
    {
      char *start = ptr;
      while(*ptr) ptr++;
      return ptr - start;
    }
    
    int strlen(char *ptr);

    int main(){
      char a[] = "hello world";
      printf("length is %d\n", strlen(a));
    }
      
  \end{code}
\end{frame}

\begin{frame}
  \frametitle{Copying string}
  \begin{code}
    void strcpy(char *src, char *dest) 
    {
      while(*src)
      {
        *dest = *src;
        dest++; src++;
      }
    }
  \end{code}
\end{frame}
\end{document}