REACH TEST REVIEW

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REACH TEST REVIEW

• CECS 121 EXAM 1

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Parts of the Program

• / C Programming for the Absolute Beginner /
• // by Michael Vine
• include ltstdio.hgt
• include ltstdlib.hgt
• main()
• printf(\nC you later\n)
• system(pause)

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(No Transcript)
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Program Statements

• Serve to control program execution and
  functionality. Must end with a semicolon() with
  the exception of
• Comments / /
• Preprocessor Directives include or define
• Begin and end program identifiers
• Function definition beginnings main()

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The main function

• Functions allow you to group program statements
  under one name
• C is case-sensitive so main(), MAIN(), and Main()
  are all different
• The main function is special because the values
  it returns are returned to the operating system
• Most main functions in this course do not take or
  pass information to the operating system

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Escape Sequences

• Definition Escape sequences are specially
  sequenced characters used to format output
• \
• Ex printf( \ This is quoted text \ )
• \
• Ex printf( \n A single quote looks like \
  \n)
• \ \ Comment Block

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Directives

• include ltstdio.hgt
• Using a directive to include a header file
• stdio.h standard input output header file
• stdlib.h system commands

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Memory

• A computers long-term memory is called
  nonvolatile memory and is generally associated
  with mass storage devices, such as hard drives.
• A computers short term memory is called volatile
  memory. It loses is data when power is removed
  from the computer

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Data Types
Data Type Description Declaration Example
Integer Whole numbers, positive or negative int x -3 , 0, 3 , 29
Floating-point number All numbers, positive or negative, decimals and fractions float x -0.35543 , 0.00, 554433.33281
Character Representations of integer values known as character codes char x m, M,
To declare a constant (read only) value const
int x 20 const float PI 3.14
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Variable Types
TYPE SIZE VALUES
bool 1 byte true (1) or false (0)
char 1 byte a toz , A to Z, 0 to 9, space, tab, and so on
int 4 bytes -2,147,483,648 to 2,147,483,647
short 2 bytes -32,768 to 32,767
long 4 bytes -2,147,483,648 to 2,147,483,647
float 4 bytes - (1.2 x 10-38 to 3.4 x 1038)
double 8 bytes - (2.3 x 10-308 to -1.7 x 10308)
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Printf() Scanf()

• Can you explain what the code is doing?

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Conversion Specifiers

• Character - c
• Integer - d
• Float (decimal)- f
• String - s
• Printf Format Tags
• flagswidth.precisionlengthspecifier
• .precisionspecifer -gt .2f

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Can you predict the printout?

• int main()
• printf (c c \n", 'a', 65)
• printf (" 10d \n", 1977)
• printf ("010d \n", 1977)
• printf ("floats 4.2f \n", 3.1416)
• printf ("s \n", "A string")
• printf(f \n, 55.55)
• return 0

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Printouts

• printf (c c \n", 'a', 65) aA
• printf ("d ld\n", 1977, 650000L) 1977650000
• printf (" 10d \n", 1977)
  1977
• printf ("010d \n", 1977) 0000001977
• printf ("floats 4.2f \n", 3.1416)
  3.14
• printf ("s \n", "A string") A string
• Can you create a tabular data using printf?

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Review Printing with Precision
Example Printout
printf(.1f,3.123456) 3.1
printf(\n.2f,3.123456) 3.12
printf(\n.3f,3.123456) 3.123
printf(\n.4f,3.123456) 3.1235
printf(\n.5f,3.123456) 3.12346
printf(\n.6f,3.123456) 3.123456
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Scanf

• Syntax
• scanf(conversion specifier, variable)

Conversion Specifies Description
d Receives integer value
f Receives floating-point number
c Receives character
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Can you predict the printout when the user enter
2 and 4?

• include ltstdio.hgt
• main()
• int iOperand1 0
• int iOperand2 0
• printf(\n Enter first operand )
• scanf(d, iOperand1)
• printf(\n Enter second operand )
• scanf(d, iOperand2)
• printf(The result is d \n, 24/(iOperand1
  iOperand2)6/3)

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Arithmetic and Order of Precedence
Operator Description
Multiplication
/ Division
Modulus (remainder)
Addition
- Subtraction
Order of Precedence Description
( ) Parentheses are evaluated first, from innermost to outermost
, /, Evaluated second, from Left to Right
, - Evaluated last, from Left to Right
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Can you predict the printout?

• include ltstdio.hgt
• main()
• int x 4
• int y 9
• int result1, result2
• result1 y/x
• result2 yx
• printf(The result is d.d \n, result1,
  25result2)

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Conditions and Operators
Operator Description
Equal to
! Not Equal
gt Greater Than
lt Less Than
gt Greater Than or Equal to
lt Less Than or Equal to
Order of Precedence Description
AND condition
OR condition
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Boolean Operators

• Do you know the answers to these?
• A. !( 1 0 )
• B. !( 1 1 0 )
• C. !( ( 1 0 ) 0 )

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Boolean Operators Quiz Answers

• A. !( 1 0 ) ANSWER 0
• B. !( 1 1 0 ) ANSWER 0 (AND is
  evaluated before OR)
• C. !( ( 1 0 ) 0 ) ANSWER 1 (Parenthesis
  are useful)

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If Statements
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Quiz

• Can you write code that will ask a user to enter
  a number 1 , 2 , or 3 and print out the
  following

User Input Printout
1 1 is the loneliest number
2 2 is better than 1
3 3s a crowd
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Answer

• include ltstdio.hgt
• int main()
• int a
• printf (Enter one of the following d, d, or
  d\n, 1, 2, 3)
• scanf(d, a)
• if(a1 a2 a 3)
• if(a1)
• printf(\n d is the loneliest number \n, 1)
  
• if(a2)
• printf(\nd is better than d \n,2,1)
• if(a3)
• printf(\nd \ s a crowd \n,3)
• else

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Switch-Case Statments
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Example Switch-Case Statement
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Loops

• while ( condition ) Code to execute while the
  condition is true
• Quiz Can you write a program that prints x
• while x increments from 0 to 10?

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Answer While Quiz
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Operators Cont.
x Tells the function to use the current value
of x and increment it by 1. x Increment the
value of x by 1 and use the new value for
calculations. x-- Tells the function to use
the current value of x and decrease its value by
1. --x Decrease the value of x by 1 and use
the new value for calculations. x0 printf(The
Value of x is d, x) printf(\n The Value of
x is d,x) Would results in The Value of x
is 0 The Value of x is 2
Application of - Equivalent Equation
x y x x y
x - y x x y
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For Loop

• Often used when the of iterations is already
  known.
• Contains 3 separate expressions
• Variable initialization
• Conditional expression
• Increment/Decrement
• Try writing a program with a for loop that
  counts down from 10 seconds.

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For Loop

• include ltstdio.hgt
• main()
• int x0
• for(x10 xgt0 x--)
• printf("d \n", x)
• system("pause")

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Break/Continue Statements

• break
• Used to exit a loop. Once this statement is
  executed the program will execute the statement
  immediately following the end of the loop.
• continue
• Used to manipulate program flow in a loop. When
  executed, any remaining statements in the loop
  will be skipped and the next iteration of the
  loop will begin

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Function Prototypes Definitions

• Function Prototype Syntax
• return-type function_name ( arg_type arg1, ...,
  arg_type argN)
• Function Prototypes tell you the data type
  returned by the function, the data type of
  parameters, how many parameters, and the order of
  parameters
• Function definitions implement the function
  prototype
• Where are function prototypes located in the
  program?
• Where do you find function definitions?

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Function Prototypes

• Where are function prototypes located in the
  program?
• Answer before the Main() Function!
• Function Definitions are self contained outside
  of the Main() function

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Calling Functions
include ltstdio.hgt int mult ( int, int ) int
main() int x int
y printf( "Please input two numbers to be
multiplied " ) scanf( "d", x ) scanf(
"d", y ) printf( "The product of your two
numbers is d\n", mult( x, y ) ) getchar()
int mult (int a, int b) return a b
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Whats Wrong with This Code?
include ltstdio.hgt Void printReportHeader() ma
in() printReportHeader void
printReportHeader() printf(\n
Column1\tColumn2\tColumn3\tColumn4 \n)
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Can You Pick Out the Local and Global Variables?
include ltstdio.hgt void printNumbers() int
iNumber main() int x for(x0,
xlt10,x) printf(\n Enter a
number) scanf(d, iNumber) printNumbers
() void printNumbers() printf(\n Your
number is d \n, iNumber)
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Variable Scope

• Variable scope defines the life time of a
  variable
• Local Scope defined within functions and loses
  scope after function is finished. Can reuse in
  other functions (ex. p.123)
• Global Scope defined outside of functions and
  can be accessed by multiple functions

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Questions?