Csc 107 programming for science
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CSC 107 – Programming For Science. Lecture 28: Course Review. Final Exam. Thurs., Dec. 16 th from 8AM – 10AM in OM 201 For exam, plan on using full 2 hours If major problem , come talk to me ASAP Exam covers material from entire semester

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Lecture 28: Course Review

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Csc 107 programming for science

CSC 107 – Programming For Science

Lecture 28:Course Review


Final exam

Final Exam

  • Thurs., Dec. 16thfrom 8AM – 10AM in OM 201

  • 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 midterm


Positional notation

Positional Notation

  • To convert dn...d3d2d1d0 intodecimal:


Converting decimal to base b

Converting Decimal To Base-b

  • General way to convert from decimal to base-b:Whiledecimal number ≠ 0Divide decimal number by bMoveremainder to left end of answerReplacedecimal number with quotient


Programming using cin

Programming Using cin

  • Used to read one or more values at once:

    cin >> variable;

    cin >> variable1 >> variable2;

    • Reads where last cinstopped 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

Using coutto Print

  • Already seen how to print text using cout

    cout << “Hello World” << endl;

    • Prints out whatever is placed between quotes

    • endlgoes 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

Priority of Operations

  • Equations can become very complex

    • 4 + 5 * 6 * 9 - 2 + 1 = …?

  • Verystrict 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

  • My suggestion: use lots of parentheses


Compound assignment operators

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


Mathematical functions

Mathematical Functions

  • Add #include<cmath>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

Relational Operators

  • < (less than)

  • > (greater than)

  • <= (less than of equal to)

  • >= (greater than of equal to)

  • != (inequality ≠)

  • == (equality – if two things have same value)

    • NOT the same as assignment (=)


Not gate

x

a

NOT Gate

  • Simplest gate: computes opposite of input

    • Output false when input true

    • Output true when input false

  • Written in C++ as !a("bang a")

    • a is gate’s input

    • x is gate’s output


Or gate

a

x

b

OR Gate

  • Equivalent to addition in Boolean algebra

    • If either input istrue is going to be checked

    • true when either aORb aretrue; false otherwise

  • Written in C++ asa || b

    • a & b are inputs; x is output


And gate

a

x

b

AND Gate

  • Equivalent to multiplication in Boolean algebra

    • If both inputs are true is going to be checked

    • True when aANDb are true; false otherwise

  • Written in C++ asa && b

    • a & b are inputs; x is output


If statement

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 ifends

    • 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

if– else if– elseUsage

  • Must begin with ifstatement at the start

    • This is required; what would we be saying elseto?

    • Onlyrequired part of this entire process

  • Can then have zero or more elseifs

    • Tests can be anything; do not have to be related

    • Until one is true, will be examined one-by-one

    • Execute 1st clause where true expression is found

  • Only at the very end can have else clause

    • If nothing else matches then elseis executed


Executing switch statement

Executing switchStatement

  • Evaluates expression

  • Finds matching caseor default(if it exists)

    • If no default, may not have match - skips switch

  • Execution starts at 1stmatching label

    • Execution will continue until break; found

    • Will continue into next case if break; is not hit

  • Restarts running after switchonce breakhit

    • May reach end of switchwithout a break

    • Continues running code after switch


While loop

whileLoop

while (expression) { statement; ...}

  • Evaluates expressionto 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

forLoop

for (initialization;expression;update) { statement; ...}

  • initializationrun once before loop start

  • Loop termination condition is expression

    • Boolean expression checked at start of each pass

    • Re-executes entire loop body if expression is true

    • Once expression found to be false, loop is over


Function definition

Function Definition

  • List prototypes for functions near top of file

    • Similar, but prototypes end with semi-colon

  • Return type, name, & parameterslisted at start

    • After these are listed, need an open brace

    • Function goes until closing bracefloat squareNumber(float x){…}double computeAvg(int x, int y){…}intpromptAndReadInput(){…}void noReturnAndNoParams(){…}


Return statement

returnStatement

  • Function ends when returnis executed

    • Any and all code after returnwill be ignored

    • Calling function will resume its execution

    • There are no errors or warnings for this common bug


Declaring arrays

Declaring Arrays

  • With the array, have entries of given type

    • Each entry like variable & can be used as such

    • Each entry is independent of all other entries

  • Type, name, & sizeneeded for array declaration

    intplanetsWeight[NOT_PLUTO];float armada[MAX_SHIPS];double annualIncomes[MAX_LIFETIME];char responses[17];long timeToWait[35];


String theory

String Theory!

  • cString type does not exist

  • Just an array of charmade to look fancy

    • One slight wrinkle: cString ends with null character

    • Since C++ does not know array’s size, but we need it

  • Null character is charwith value of 0

    • Written as ‘\0’ if used in a program

    • Unprintable, only used to mark end of cString


Program basics for files

Program Basics For Files

  • All built-in file I/O code means adding to header

    #include <fstream>

    • Place with other #includes 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

Opening a File

3

  • Within program, may use file in 2 possible ways

    • To read file, ifstreamvariables will be needed

    • Need variable of type ofstreamto write to file

    • Open ofstream2 different ways depending on use

      ofstreamnukeIt("byebye.txt");ofstreambegone;begone.open("erasedOld.dat");ofstreamkeepIt("saved", ios::app);ofstreamfaithAlone;faithAlone.open("preserve", ios::app);


Read file w ifstream variable

Read File W/ifstreamVariable

  • Used to read one or more values at once:

    ifstreammyFile;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

Print to File With ostream

  • Easy to output: output via ostreamvariable

    ofstreamoutFile;outFile << “Hello World” << endl;

    • Prints out whatever is placed between quotes

    • Value of variable printed if variable not in quotes


Declaring an pointer

Declaring an Pointer

  • Must declare pointer before use

    • This should not be surprise, just like any variable

  • Type &name required (as with all declarations)

    • As with any other variable, typical name rules apply

    • Include asterisk before name within declaration

    • Variable is now a pointer to requested type

    • Initial value is unknown

      int*jennifer;char*pointerToChar;double*down;


And operators

& and * Operators

  • & operator gets the address of a variable

    • 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

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

Using structs

  • Can assign structvariablesto 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 structvariables

    • For any legal use, individual fields always available

  • Arrays of structscan also be declared

    • Within the array, each entry is structvariable


Subtle hint

“Subtle” Hint

Do NOT bother with

memorization

Be ready to lookup &use information quickly


Final exam schedule

Final Exam Schedule

  • Lab Mastery Exam is:Tues., Dec. 14thfrom 10:15AM – 11:15AM in OM 115

  • Final Exam is: Thurs., Dec. 16thfrom 8AM – 10AM in OM 201


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