1. UMBC CMSC 104 – Section 01, Fall 2016
Exam 2 Review

2. Notes & Announcements Project 8 due… now!
Will review in a moment
Today is final day to fill out course evals
Look for from

3. Final Exam The final exam is scheduled for: Thursday, December 15th
6:00 – 8:00 PM
Engineering 122 (here)
The exam will be on paper – bring a pencil!
You may bring a calculator. You probably won’t need it.
NO PHONES OR COMPUTER USAGE ALLOWED
Bring your UMBC ID!

4. Requesting Feedback
Did you prefer the course website over Blackboard? Why?
Would you have preferred less projects and another exam? Why?
Would you have preferred more in-class labs, assuming they didn’t count for EC?
Other comments?

5. Exam 2 Review

6. Overview If it’s in the slides, it’s fair game Broad Concepts
Arithmetic Ops (+, -, *, /, %)
Assignment Ops (++, --, +=, -=, etc)
Relational Ops & Selection Statements (if, else if, else)
For loops and While loops
Switch Statements
Functions
Arrays
Searching & Sorting Algorithms
Pointers

7. Arithmetic Operators in C
Name
Operator
Example
Addition +
num1 + num2
Subtraction -
initial – spent
Multiplication *
fathoms * 6
Division /
sum / count
Modulus %
m % n

8. Rules of Operator Precedence
Operator(s)
Precedence & Associativity
( )
Evaluated first. If nested (embedded), innermost first. If on the same level, left to right.
* / %
Evaluated second. If there are several, evaluated left to right.
+ -
Evaluated third. If there are several, evaluated left to right. =
Evaluated last, right to left.

9. Increment and Decrement Operators
The increment operator ++
The decrement operator --
Precedence: lower than (), but higher than * / and %
Associativity: right to left
Increment and decrement operators can only be applied to variables, not to constants or expressions

10. Assignment Operators = += -= *= /= %= Statement Equivalent Statement
= += -= *= /= %=
Statement Equivalent Statement
a = a + 2 ; a += 2 ;
a = a - 3 ; a -= 3 ;
a = a * 2 ; a *= 2 ;
a = a / 4 ; a /= 4 ;
a = a % 2 ; a %= 2 ;
b = b + ( c + 2 ) ; b += c + 2 ;
d = d * ( e - 5 ) ; d *= e - 5 ;

11. Relational Operators Relational expressions evaluate to the integer
< less than
> greater than
<= less than or equal to
>= greater than or equal to
== is equal to
!= is not equal to
Relational expressions evaluate to the integer
values 1 (true) or 0 (false).
All of these operators are called binary operators because they take two expressions as operands.

12. Logical Operators So far we have seen only simple conditions.
if ( count > 10 ) . . .
Sometimes we need to test multiple conditions in order to make a decision.
Logical operators are used for combining simple conditions to make complex conditions.
&& is AND if ( x > 5 && y < 6 )
|| is OR if ( z == 0 || x > 10 )
! is NOT if (! (bob > 42) )

13. Nesting of if-else Statements
if ( condition1 ) {
statement(s) }
else if ( condition2 )
/* more else clauses may be here */
else
statement(s) /* the default case */

14. The while Repetition Structure
while ( condition ) {
statement(s) }
The braces are not required if the loop body contains only a single statement. However, they are a good idea and are required by the 104 C Coding Standards.

15. The for Loop Repetition Structure
The for loop handles details of the counter-controlled loop “automatically”.
The initialization of the loop control variable, the termination condition test, and control variable modification are handled in the for loop structure.
for ( i = 1; i < 101; i = i + 1) {
initialization modification
} test

16. The switch Multiple-Selection Structure
switch ( integer expression ) {
case constant1 :
statement(s)
break ;
case constant2 :
. . .
default: }

17. Examining PrintMessage
#include <stdio.h>
void PrintMessage ( void ) ; function prototype
int main ( ) {
PrintMessage ( ) ; function call
return 0 ; }
void PrintMessage ( void ) function header
printf (“A message for you:\n\n”) ; function
printf (“Have a nice day!\n”) ; body
} function definition

18. Array Declaration and Initialization
int numbers[5] ;
The name of this array is “numbers”.
This declaration sets aside a chunk of memory that is big enough to hold 5 integers.
It does not necessarily initialize those memory locations to 0 or any other value. They may contain garbage.
Initializing an array may be done with an array initializer, as in :
int numbers[5] = { 5, 2, 6, 9, 3 } ;
numbers 5 2 6 9 3

19. Accessing Array Elements
Each element in an array has a subscript (index) associated with it.
Subscripts are integers and always begin at zero.
Values of individual elements can be accessed by indexing into the array. For example,
printf(“The third element = %d.\n”, numbers[2]);
would give the output
The third element = 6.
numbers 5 2 6 9 3

20. Don’t Forget… Searching & Sorting Pointers Searching Algorithms
Sorting Algorithms
Efficiency
Pointers
Definition of a pointer
Types of pointers
Uses for pointers

21. Questions?