CSC 234 Final
scanf(" ", &a, ...)
" ": format string &a: addresses &variable The scanf function allows you to enter values from the keyboard when the program is executed
while( )
"while (condition)" { statements; } The condition is evaluated before the statements within the loop are executed. If the condition is false, the loop statements are skipped, and execution with the statement following the while loop
Format codes (output) %d %e %% %10d
%d: int to decimal %e: float to expontetial format %%: a % sign in the output %10d: int to decimal with minimum field width
logical operators && || !
&& and || or ! not equal to?
.bash_profile
(dot file) at login -login username and password; place to put stuff that applies to your whole session, such as programs you want to start when you login and environmental variable definition -It's a shell script that gets executed every time the shell starts up. It's located in your home directory. Say you want an environment variable set to something every time your shell starts--You can just put that command into the ~/.bash_profile file, and it'll do that automatically.
.bashrc
(dot file) at shell start -place to put stuff that applies only to bash itself, such as alias and function definitions, shell options, and prompt settings -used to open a new terminal window after you have logged in
+ - / *
+ addition - subtraction / division * multiply
long integer data
A long integer can represent a whole integer number whose range is greater than or equal to that of a standard integer on the same machine -64 bits
loop
A set of statements that are repeated
standard input file
-keyboard - "stdin" --> going into the program
standard output file
-terminal screen - "stdout" -->stream where a program writes its output data
EOF from scanf
-way of ending loop EOF INDICATOR: a special character at the end of a file to indicate that the end of the file has been reached EOF CHARACTER: a special character that indicates the end of a text stream -the fscanf function can be used to detect when the end of the data has been reached in a file. Scanf returns the number of values successfully read each time that it is executed. If function returns a different value from what was supposed to read, then the end of the data file has been reached
sentinel value
-way of ending loop -special data values that are used to indicate or signal the last record of a file
comments
/* blahblah */ // blahblah -avoid useless comments, comment more on why rather than what
variable
A memory location that is given a name and whose contents may or may not change during the execution of a program
function
A module that returns at most one value to the invoking statement
source program code
A program in a high- level code -what you write -original C program
object program code
A program in machine language -what gets run -machine language version of original C program
compiler
A program that translates a program in a high level language into machine language
comparison operators < > <= >= ==
< is less than > is greater than <= is less than or equal to >= is greater than or equal to == is equal to
general form of a loop
<<<initialize>>> while(<<continue conditions>>) { <<<computation>>> [includes output] <<<update>>> }
a = array[i+1] + b
= arrayname[subscript] +b
statement
A comment or an instruction in a program
dot files
A configuration file usually stored in users home directory. Dot files are used to configure the settings for many unix programs -name: .name -used to store configurations for different applications but they are sometimes used otherwise as well
directory
A file system cataloging structure in which references to other computer files, and possibly other directories, are kept -a location where files are kept in a list
machine language
A language in which instructions are written as binary strings -low level language -tied closely to the design of the computer hardware -usually written in 2 symbols, 0 and 1 (bits)
file
A location where data is stored -resource for storing info, which is available to a computer program and is usually based on some kind of durable storage -computer files are the "documents" in a library
short integer data
A short integer can represent a whole number which may take less storage, while having a smaller range, compared with a standard integer on the same machine -32 bits +/- 2 billion - -32768 to 32767
assignment
A statement that assigns a value to an identifier
literal/constant
A value that does not change during the execution of a program
redirection of input
Redirection is usually implemented by placing certain characters between commands < to redirect input > to redirect output
character data
Character (char): a data type which represents info that is not restricted to being numeric Character data -a variable that is going to contain a character is defined as an integer or as a character data type
.c file
Code stored in a "C" type file
cd
Command line arguement used to change the current working directory in operating systems -change current directory location
mkdir
Command that creates one or more new directories specified by the directory parameter
gcc
Compile a program written in C (command)
Designing a program
Design the program -given a problem -clarify the problem -think about the DATA -->outline program input->computations/programs->output
alias command
Enables a replacement of a word by another string alias a.out= ./a.out
C
Programming language
floating point data
Floating-point value: a value that can represent both integer and non-integer values Float: 6 digits of precision -max exponent 38 -max value 3.4028323e388 Floating point numbers: how computer stores things--> scientific notation
integer (int) data
Fundamental type used to define numeric variables holding whole numbers ex: int variable --> you created an integer variable
input/ output
Inputs are signals or data received by the system, outputs are signals or data sent from it -communication between computer and outside world (human or another information processing system)
man pages
Manual page is software documentation -include info on computerprograms, format standards, and conventions, and even abstract concepts
file names
Name used to uniquely identify a computer file stored in a file system
Designing a program
Outline program FIll in Outline Test Fix bugs
memory (RAM)
Part of a computer that stores information -RAM= random access memory -type of computer memory that can be accessed randomly; any byte can be accessed w/o touching the preceding bytes
path name
Path to a file is its official name "path name" -the set of directories that have to be traversed to get a file -way of giving an address for the location of a file
flow of control
Refers to the order in which the individual statement, instructions, or functions calls of an imperative or a declarative program are executed or evaluated
ls
Shows what files you have (command)
nano
Text editor for unix-like computing systems (command)
current working directory
The directory or folder that is currently open -will be shown as the prompt or can be seen by using the pwd command
terminal
The hardware used to enter, retrieve, and display electronic data (command) -program that provides a line interface to control the underpinnings of the unix based operating system
string literal (" ")
The representation of a string value within the source code of a computer program -quoted sequence of characters ex: x= "foo" --> "foo" is string literal with value foo
sqrt function
The sqrt( ) function returns the non-negative square root of x
root node
Unix uses a hierarchical structure for organizing files and directories, often referred to as a directory tree - the tree has a single root node, the slash character (/), and all other directories are contained below it
/
Used to access a file in the current directory or move to another one -reserved for trees, can't be in file name
#include
Used to access function definitions defined outside of a source code -almost always used to include header files, which are files that mainly contain function declarations and #define statements -preprocessor directories provide instructions that are performed before the program is compiled
file system
Used to control how data is stored and retrieved -w/o file system, info placed in a storage area would be one large body of data with no way to tell where one piece of info stops and the next begins
mv command
Used to move and rename files or directories ex: mv hate love -->changes to old name of hate to love
When do you need " " around file names?
When a file has spaces you need " " around the whole name
\n \t \r \\ \'
\n= newline \t= horizontal tab \r= carriage return \\= backslash sign \'= single quote
first expression (a) evaluated may avoid second expression being evaluated (b)
a && b (if a is false) a || b (if a is true)
array
a data structure that allows a group of values to be represented with the use of a common name and to be distinguished via subscripts
for loop
a loop that is executed a specified number of times
while loop
a loop that is executed as long as a condition is true
Unix
an "operating system", the most basic program that controls what a computer does and provide easier access to the hardware for the programs you think of as the computer
int arrray[10]
basetype arrayname[size]
cat
concatenate files and print on the standard output
( ) in expressions
construct permits arithmetic expansion and evaluation
a.out file
file format for outputting code -runs the program
for
for (init; condition; increment)
gcc -lm
gcc -lm is needed to compile a program that refers a function from the math library
if statement
if ( << true/false expression >> ) { << computations if true >> } else { << computations if false>> }
else clause of an if
if (condition) { Statement1; Statement2;} else { Statement3; Statement4; } In these type of statements, group of statements are executed when condition is true. If condition is false, then else part statements are executed.
if statements
if (condition) { Statements; } In these type of statements, if condition is true, then respective block of code is executed.
nesting control statements
if (condition1) { Statement1; } else_if (condition2) { Statement2; } else Statement 3; If condition 1 is false, then condition 2 is checked and statements are executed if it is true. If condition 2 also gets failure, then else part is executed.
.
move through directories -current directory
..
move through directories -previous directory, move back -parent directory
\n
new line
!=
not equal to A!=B means A is not equal to B
more
screen-by-screen view of file(s)
