CSC 107 – Programming For Science

Final Exam  Fri., Dec. 14 th from 12:30PM – 2:30PM in SH1028  For exam, plan on using full 2 hours  If major problem, come talk to me ASAP  Exam covers material from entire semester  Open-book & open-note so bring what you’ve got  My handouts, solutions, & computers are not allowed  Cannot collaborate with a neighbor on the exam  Problems will be in a similar style to midterms

Positional Notation  To convert d n... d 3 d 2 d 1 d 0 into decimal: From base-b d 0 * b 0 d 1 * b 1 d 2 * b 2 d 3 * b 3 … + d n * b n

Converting Decimal To Base-b  General way to convert from decimal to base-b: While decimal number ≠ 0 Divide decimal number by b Move remainder to left end of answer Replace decimal number with quotient

Programming Using cin  Used to read one or more values at once: cin >> variable ; cin >> variable1 >> variable2 ;  Reads where last cin stopped reading input  Automatically skips past whitespace  Data type of variable determines what is read  Stops reading at first non-usable value in input  If input is not usable, will set variable equal to 0

Using cout to Print  Already seen how to print text using cout cout << “Hello World” << endl;  Prints out whatever is placed between quotes  endl goes to next line and prints out immediately  Can format output in variety of ways  Print numbers to preset level of precision  Use fixed format versus which ever makes sense

Priority of Operations  Equations can become very complex  * 6 * = …?  Very  Very strict order of operations used by computer  ( ) Solve from inner- to outermost  + (positive) & - (negative) Solve from right to left  * & % & / (division) Solve from left to right  + (addition) & - (subtraction) Solve from left to right use lots of parentheses  My suggestion: use lots of parentheses

Compound Assignment Operators  Short simple operators that allow us to be lazy  Save some typing for several common actions  Lowest priority operation; expression evaluated first OperatorEquivalent C++ Expression a += 2;a = a + 2;a = a + 2; b -= d;b = b – d;b = b – d; c *= ;c = c * ( ); d /= 0.3 * e;d = d / (0.3 * e);

Mathematical Functions  Add #include at top of file  All these functions return a value  Will NOT change argument’s value sin( x ), cos( x ), tan( x ), asin( x ), atan( x ), log10( x ), sqrt( x ), log( x ), exp( x ), pow( x, y ), floor( x ), ceil( x )

Relational Operators  < ( less than)  > ( greater than)  <= ( less than of equal to)  >= ( greater than of equal to)  != ( inequality ≠)  == ( equality – if two things have same value) assignment (=)  NOT the same as assignment (=)

NOT Gate  Simplest gate: computes opposite of input  Output false when input true  Output true when input false !a  Written in C++ as !a ("bang a")  a is gate’s input a !a!a!a!a true false a

OR Gate  Equivalent to addition in Boolean algebra  If either input is true is going to be checked  true when either a OR b are true; false otherwise a || b  Written in C++ as a || b  a & b are inputs ab a || b false true false true a b

AND Gate  Equivalent to multiplication in Boolean algebra  If both inputs are true is going to be checked  True when a AND b are true; false otherwise a && b  Written in C++ as a && b  a & b are inputs ab a && b false true false true a b

if (…) statement  First evaluates expression in parenthesis  Add opening brace ( { ) after closing parenthesis  Can now write all statements to execute  Add closing brace ( } ) to show where if ends  If expression false, execution restarts at that point  If expression is true, executes code in block  Skips over block, when expression is false

if – else if – else Usage  Must begin with if statement at the start  This is required; what would we be saying else to?  Only  Only required part of this entire process  Can then have zero or more else if s  Tests can be anything; do not have to be related  Until one is true, will be examined one-by-one  Execute 1 st clause where true expression is found  Only at the very end can have else clause  If nothing else matches then else is executed

Executing switch Statement 1. Evaluates expression 2. Finds matching case or default (if it exists)  If no default, may not have match - skips switch 3. Execution starts at 1 st matching label  Execution will continue until break; found  Will continue into next case if break; is not hit 4. Restarts running after switch once break hit  May reach end of switch without a break  Continues running code after switch

while Loop while (expression) { statement;... }  Evaluates expression to find its value  If true, executes entire loop body  Re-check after each pass through loop, only  Continue with loop while expression checks true

for Loop

Function Definition

return Statement

Declaring Arrays

String Theory!

Program Basics For Files  All built-in file I/O code means adding to header #include #include  Place with other #include s to use files in program  Even if no files are used, no cost to adding this line  Must specify namespace of file I/O code, also  If you really want, this can be done individual but… using namespace std;  much easier and probably habit by now anyway

Opening a File  Within program, may use file in 2 possible ways  To read file, ifstream variables will be needed  Need variable of type ofstream to write to file  Open ofstream 2 different ways depending on use ofstream nukeIt("byebye.txt"); ofstream begone; begone.open("erasedOld.dat"); ofstream keepIt("saved", ios::app); ofstream faithAlone; faithAlone.open("preserve", ios::app); 3

Read File W/ ifstream Variable  Used to read one or more values at once: ifstream myFile; myFile >> variable ; myFile >> variable1 >> variable2 ;  Starts where last read stopped reading input  Automatically skips past whitespace  Data type of variable determines what is read  Stops at first non-usable value found in the input  If input is not usable, will set variable equal to 0

Print to File With ostream  Easy to output: output via ostream variable ofstream outFile; outFile << “Hello World” << endl;  Prints out whatever is placed between quotes  Value of variable printed if variable not in quotes

Declaring an Pointer

& and * Operators variable  & operator gets the address of a variable  Used only with variables  Used only with variables, including array elements  Types must match, no automatic promotion possible  Pointers to pointers okay, but needs to be type **  Follow the pointer to get value at location with *  Only used with pointers, as * could also be multiply double x, *y = &x; int *a, *b = &a; float *c = a, d = *a;

Pointers versus Arrays  Both types of variables store an address  Can be assigned to one another if types match  To access value, can either use * or [ index ]  *p same as p[0] - they are "synonyms" in C++  Arithmetic works similarly - *(p+5) same as p[5]  Do not get carried away exploiting this idea  Unlike arrays, memory not reserved for pointer  Arrays not used to alias other variables (usually)

Using struct s variables  Can assign struct variables to one another  Variables must be of identical struct types  Copies value of all fields but still remain independent  Locations will be same, since pointers & arrays aliased  In all other situation, must use fields  Cannot add, multiply, compare struct variables  For any legal use, individual fields always available  Arrays of struct s can also be declared  Within the array, each entry is struct variable

“Subtle” Hint

For Final  You can use on this final:  Your textbook & notes  At the same time, you may NOT use:  Computer, calculator, cell phone, or similar  Copies of daily activities and/or solutions  Friends, Romans, countrymen or their ears

How to Prepare for Midterm DODON'T  Redo activities, labs, weekly…  Make cheat sheets for the test  Review how parts of C/C++work  Assume notes replace studying  Ever, ever invade Russia in winter  Assume you'll pass cause you're cute

How to Prepare for Midterm DODON'T  Redo activities, labs, weekly…  Make cheat sheets for the test  Review how parts of C/C++work  Assume notes replace studying  Ever, ever invade Russia in winter  Assume you'll pass cause you're cute

How to Prepare for Midterm DODON'T  Redo activities, labs, weekly…  Make cheat sheets for the test  Review how parts of C/C++work  Add post-its to important pages  Assume notes replace studying  Ever, ever invade Russia in winter  Drink case of 40s before test  Use post-its as clothing

Final Exam Schedule  Lab Mastery Exam is: Tues., Dec. 11 th 2:45PM – 3:45PM in SH1008  Final Exam is: Fri., Dec. 14 th from 12:30PM – 2:30PM in SH1028