1. Header files (answers to jit-anonymous questions)
Angle brackets <> specify header files found in standard locations, double quotes “” specify current directory (or non standard location)
<iostream.h>, <ctype.h>
“ctimer.h”, “date.h”
in new versions of C++, the .h isn’t used for standard C++ classes, e.g., <iostream>, <string>, STL <vector>
on our system these files just use #include <iostream.h>, but could pre-compile or otherwise optimize the headers
on other system using the .h puts classes into the global namespace, otherwise must qualify use: std::cout vs cout

2. Standard/STL classes vs libtapestry classes
libtapestry strings aren’t as efficient, e.g., no sharing on assignment
reference counted, shared storage
copy on write
always copy (libtapestry)
shared vs static libraries
static code stored in executable when compiled
shared/dynamic linked when program run
advantages?
string a = “hello”;
string b = a;
“hello”
libtapestry.a a b
“hello”
standard (libg++.so)
“hello” a b
b[0] = ‘j’; // what happens?

3. STL classes (e.g., vector)
In general, the STL classes aren’t safe, e.g., bad index not checked
on our systems, a “safe” version of classes can be used by using #define __STL_DEBUG before any #include
specific differences in STL vector vs libtapestry vector
STL libtapestry
size() length()
push_back() append()
append/push_back works differently: size() in libtapestry is number of times append called
libtapestry vector, map, stack, queue are as efficient as STL classes (sometimes more efficient) and are safe

4. Using the system, dot files
The shell is the program you type commands at
different shells: sh, csh, bash, ksh, tcsh
use tcsh unless you’re positive you want something else
the shell looks at your PATH environment variable to determine where commands you type are found
uses directories specified in left-to-right order
setenv PATH /afs/acpub/project/cps/bin:${PATH}
also /bin/sh variable called path (lower case) set differently
.cshrc file, used each time you start a shell
.login file, used when you log in
.emacs file, used when you launch emacs/xemacs