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Notes for Lecture 5 - January 29, 2008
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* General discussion of how to learn a second language
** Read sample code
** Read textbook quickly to get overview
** Ask questions

* Type char
** sizeof(char) == 1
** can be signed or unsigned
** character constants e.g. 'a' have type int
** char is a numeric type; can do arithmetic on them
Example:  The ASCII character code for 'a' is 96.
putchar(96) prints the letter 'a'; so does putchar('a').
putchar(97) prints the letter 'b'; so does putchar('a'+1).

* Defining pi (needed in PS2)
** #define PI 3.14159
This substitutes the numeric literal for each occurrence of PI.
Accurate only to number of digits specified.
** const double pi = 2*acos(0.0);
This computes pi using the math library function acos() and
uses the result to initialize a read-only variable "pi".
** const
Means value can't be changed after initialization.
Otherwise just like a variable.

* Overview of scanf() and sscanf()
** Character buffer is array of characters
*** Example:  char buf[100];
** Using scanf() format to read line
*** Format "%99[^\n]"
*** ret = scanf( "%99[^\n]", buf );
Reads to end of line or until 99 characters have been read.
Appends null character '\0' to buffer.
Returns 1 if 1 or more characters found.
Returns 0 if line is empty.
Returns EOF on end of file or read error.
*** & not needed in front of buf
Array names are already considered to be pointers.
** sscanf()
*** Like scanf(), but reads from a string
*** Example:  ret = sscanf( buf, "%i", &x )
Reads a decimal integer from buf, converts it to an int, and
stores it in x.
Returns 1 if successful.
Returns 0 if a non-integer was encountered.
Returns EOF if end of buffer reached.

* blocks and scoping
** block can be used where a statement is permitted
** blocks can contain declarations and executable statements
** names declared in a block are not visible outside of the block

* Statements
** if
** do ... while
** while
** switch
** break
** continue
** goto
Rarely needed.  Don't use in this course without permission.