1. Instructor: Dr. Michael Geiger Spring 2019 Lecture 13: Exam 1 Preview
EECE.3220 Data Structures
Instructor:
Dr. Michael Geiger
Spring 2019
Lecture 13:
Exam 1 Preview

2. Data Structures: Exam 1 Preview
Lecture outline
Announcements/reminders
Late HW 1 submissions due by end of day
Solution to be posted Saturday morning
Program 2 to be posted; due date TBD
Exam 1: Monday, 2/25, 3-5 PM, Ball 214
Will be allowed two double-sided 8.5” x 11” note sheets
No electronic devices
Today’s lecture: Exam 1 Preview
General exam notes
Review of material
5/6/2019
Data Structures: Exam 1 Preview

3. Data Structures: Exam 1 Preview
Exam 1 notes
Allowed two 8.5” x 11” double-sided sheets of notes
No other notes, electronic devices (calculator, phone)
Exam will last two hours
We’ll start at 3:00—please be on time!!
Covers all lectures through Lec. 12
No questions on
Basic C++ structure (namespaces, <iostream>, etc.)
File organization (.h/.cpp files for structs/classes)
Abstract data types
Exam sections (1+ questions in each)
Input/output
C style structures
Functions
Strings
Algorithmic complexity
Classes
5/6/2019
Data Structures: Exam 1 Preview

4. Data Structures: Exam 1 Preview
Review: Basic I/O
Output (cout) streams
Can output multiple values in same statement
cout << "x= " << x << ", y=" << y << endl;
Recall endl ≈ '\n' + flush output stream
Input (cin) streams
Use cin to read values into variables
E.g., cin >> x;
Skips whitespace characters
Can cause problems if input doesn’t match variable type
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Data Structures: Exam 1 Preview

5. Data Structures: Exam 1 Preview
Review: File I/O
File stream objects
Must include <fstream>
ifstream (input) or ofstream (output)
Have methods for file open/close
File I/O syntax similar to standard I/O
Replace cin/cout with appropriate stream object
Same operators used: << >>
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Data Structures: Exam 1 Preview

6. Review: Output manipulators
setprecision: change number of digits displayed to the right of the decimal point
fixed: fixed format (no scientific notation)
showpoint: force decimal point (and trailing zeros) to be shown
Default behavior (without showpoint) is to not show trailing zeros
Default precision (with showpoint) is 6
Reset with noshowpoint
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Data Structures: Exam 1 Preview

7. Review: Output manipulators (cont)
showpoint does not imply fixed format
Could be fixed point, could be scientific notation
Scientific notation used if
precision < # digits before decimal point
Default behavior: precision = sig. figures
After fixed: precision = digits after point
Clearing fixed flag: defaultfloat
There aren’t just two options …
… but we’re not going to discuss the other ones
5/6/2019
Data Structures: Exam 1 Preview

8. Review: Characters and input
Input (cin) streams
Use cin to read values into variables
E.g., cin >> x;
Skips whitespace characters
Input value must be compatible with type of x
Reading n characters: cin.get(buffer, n);
Reading 1 character: cin.get(ch);
Reading an entire line (at most m characters): cin.getline(buffer, m)
May need cin.ignore(x) to skip characters
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Data Structures: Exam 1 Preview

9. Review: Structures in C++
User-defined collections of data; example:
struct StudentInfo {
char first[50];
char middle;
char last[50];
unsigned int ID;
double GPA; };
Can define variables of that type
Scalar: StudentInfo student1;
Array: StudentInfo classList[10];
Pointer: StudentInfo *sPtr;
Access members using
Dot operator: student1.middle = ‘J’;
Arrow (if pointers): sPtr->GPA = 3.5;
Passed to functions by address or reference
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Data Structures: Exam 1 Preview

10. Review: Nested structures
Structures can contain other structures:
struct Name {
char first[50]; // First name
char middle; // Middle initial
char last[50]; // Last name };
struct SINew {
Name sname; // Student name
unsigned int ID; // ID #
double GPA; // Grade point
Will need multiple dot operators to access field within nested structure
Given SINew s1;
s1.sname  Name structure within s1
s1.sname.middle  middle initial of name within s1
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Data Structures: Exam 1 Preview

11. Data Structures: Exam 1 Preview
Review: Functions
Used to break programs into smaller pieces
Useful when code sequences repeated
Functions have:
An optional return value
A name
Optional arguments
Must be prototyped or written completely prior to use
C++ supports three forms of argument passing
Pass by value (also supported in C)
Pass by address (also supported in C)
Pass by reference
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Data Structures: Exam 1 Preview

12. Review: Function examples
All examples below are function prototypes
Contain information about how to call function
Return type, name, and argument list
Only arg types required, but good practice to list names
No details on operation of function (definition)
int f1();
double f2(int x, int y);
void f3(int *p1, int *p2);
void f4(int &r1, int &r2);
f3() arguments passed by address
Explicit pointer—call requires addresses: f3(&x, &y);
f4()arguments passed by reference
Aliases—call does not require addresses: f4(x, y);
f4() does have ability to modify input arguments
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Data Structures: Exam 1 Preview

13. Data Structures: Exam 1 Preview
Review: Strings
String data type found in <string> library
Concepts to work with strings
Relational operators: ==, !=, <, >, <=, >=
Character-by-character comparison using ASCII
Concatenation: +, +=
Choosing single character: [], at()
at() provides boundary checking
Substrings: substr() function
If s1 = “ECE 264”
 s1.substr(0,3) = “ECE”  3 chars starting at position 0
s1.substr(4) = “264”  all chars from position 4 to end of string
Checking string length: length(), empty() functions
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Data Structures: Exam 1 Preview

14. Review: Algorithmic complexity
Typically try to approximate worst-case computing time
Measure time as T(n), function of n
Count number of times each step in algorithm executes
Use big O notation—O(f(n))—to express order of magnitude
Choose slowest growing function that provides upper bound on execution time
Look at largest exponent in T(n) term
Ignore constants, multipliers
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Data Structures: Exam 1 Preview

15. Data Structures: Exam 1 Preview
Review: Classes
Classes allow programmer to define their own types
Objects: instances of a class
Each class typically contains
Data members: attributes for each object
Each object has own copy of data members
Member functions: Tasks specific to class
Data/functions can be public or private
Private members only accessible within member functions
Often accessed through “set”, “get” functions
Private functions also known as helper functions
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Data Structures: Exam 1 Preview

16. Review: Class Declaration
Basic syntax class ClassName { public: Declarations of public members private: Declarations of private members };
Class definition in .h file
Function definitions in .cpp file
Must specify class name with definition:
ClassName::FunctionName() { ... }
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Data Structures: Exam 1 Preview

17. Data Structures: Exam 1 Preview
Review: Constructors
Functions used to initialize an object’s data when it is created
Must be defined with the same name as the class:
e.g. GradeBook::GradeBook()
No return type
Default constructor has no parameters
Parameterized constructor takes 1+ arguments
Constructors often examples of overloaded functions
Functions with same name, different argument list
5/6/2019
Data Structures: Exam 1 Preview

18. Data Structures: Exam 1 Preview
Final notes
Next time: Exam 1—PLEASE BE ON TIME
Reminders:
Late HW 1 submissions due by end of day
Solution to be posted Saturday morning
Program 2 to be posted; due date TBD
Exam 1: Monday, 2/25, 3-5 PM, Ball 214
Will be allowed two double-sided 8.5” x 11” note sheets
No electronic devices
5/6/2019
Data Structures: Exam 1 Preview