E0001 Computers in Engineering

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E0001 Computers in Engineering

• Inputs to the Computer

2
What did we cover last week

• Variables
• why we use them
• how we name them
• how we define them
• how they work
• arithmetic operations
• print statement and zones

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A Review from Last Week - Determine variables and
outputs

• x 2
• y 3 x
• x y 5
• PRINT x 4
• y y 1
• END

• x y
• 2
• 6
• 11
• OUTPUT - 15
• 7

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Determine types of variables

• single precision
• integer
• double precision
• string variable

• total 6
• total 6
• total 6
• total 6

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Key points

• arithmetic order
• types of variables and how to assign specific
  types
• PRINT statement

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Readings and Exercises

• Schneider pp 59 - 66
• exercies 3.3 p 67 - as required
• Schneider p 69 s 17, 20, 21, 25

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Inputs to the computer

• two main ways to get information into the
  computer
• INPUT statement
• READ and DATA statement

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Input statement

• INPUT reads input from the keyboard or a file.
• LINE INPUT reads a line of up to 255 characters
  from the keyboard or a file.
• INPUT "prompt" , variablelist
  
• LINE INPUT "prompt" variable
  

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INPUT - simplest form

• INPUT variable1, variable2....
• EXAMPLES
• INPUT x
• INPUT studnumber, names
• program stops and waits for user to enter
  variables
• number and type of variables must match

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INPUT with prompt

• INPUT prompt variablelist
• INPUT enter values for a and b a, b
• enter values for a and b? 1,2
• INPUT enter values for a and b, a, b
• enter values for a and b1,2
• variablelist separated by commas
• user input must match in type and number,
  separated by commas

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• CLS
• PRINT "This is a program to print envelopes."
• PRINT "Press any key when you are ready to begin
  . . .."
• Temp INPUT(1) 'Assign value to variable
• LINE INPUT "Enter your name " YourName
• LINE INPUT "Enter your address " Address
• LINE INPUT "Enter your city, state, and ZIP code
  " CityEtc
• PRINT "Position envelope in printer and press
  Enter ."
• char 1
• Temp INPUT(char)
• LPRINT YourName LPRINT Address
• LPRINT CityEtc

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READ and DATA statements

• READ statement assigns variables from
  corresponding DATA statement
• READ variable1, variable2...
• .....
• DATA data1, data2...
• variable1 data1 variable2 data2 etc

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• following READ statements continue from data list
• cannot run out of data - OUT OF DATA ERROR
• variable types must match
• READ studnumber, names
• DATA 12345, smith

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Restore statement

• Restores data pointer to start of data
• next READ assigns from first DATA statement,
  first variable

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• What will be displayed when the following program
  is executed?
• READ a, b
• LET x a b
• READ a, b
• LET y a b
• RESTORE
• READ a, b
• LET z a - b
• PRINT x y z
• DATA 2, 4, 3, 1, 5, 3
• END

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Problem

• draw a flowchart which will
• define variables for pi, radius and circumference
  as double, integer and double respectively
• set radius 3.2, pi 22/7
• calculate the circumference
• print all variables

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Flowchart
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Dim statement

• DIM x AS LONG
• DIM y AS STRING
• DIM z AS DOUBLE
• DIM zz AS INTEGER

• x
• y
• z
• zz

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Now write the program

• DIM radius AS integer
• DIM pi AS double
• DIM circ AS double
• radius 3.2
• pi 22/7
• circ 2pir
• PRINT r,pi,circ
• Is this program correct?

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Now change the program to include INPUT statements

• DIM radius AS integer, pi AS double, circ AS
  double
• pi 22/7
• INPUT radius
• circ 2piradius
• PRINTradius radius
• PRINTpi pi
• PRINT circumference iscirc

• DIM radius AS integer
• DIM pi AS double
• DIM circ AS double
• radius 3.2
• pi 22/7
• circ 2piradius
• PRINT radius,pi,circ

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The End
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TUTORIAL

• 1. Which is the correct hierarchy for arithmetic
  operators (from those evaluated first to those
  evaluated last).
• 2. What value will be assigned to x when the
  following statement is executed?
• LET x 4 32 / 5 4

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• 3. The following statement is valid. (T/F)
• INPUT "IS THIS OK" q
• 4. The following statement is valid. (T/F)
• DATA 25, "X 16", 14
• 5. The following statement is valid. (T/F)
• INPUT x, 5

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• 6. What will be displayed when the following
  program is executed?
• DATA 5, 3
• READ c, d, e
• DATA 2, 4, 1
• READ a
• DATA b, c, d
• PRINT c
• DATA 3, 4, 2, 1, 5
• END

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• 7. What will be the output of the following
  program?
• CLS
• READ a, b, c
• PRINT a, b, c, b
• DATA The, best, "of the"
• END

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• 7. Evaluate the following numeric expressions.
• (a) 2 - (1 - 1)
• (b) 12 / 4 3 2
• (c) 2 9 2
• (d) 10 - 3 2
• (e) How would you modify the
  expression in (d) without changing any of the
  numbers so that it evaluates to 49?

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Problem

• Suppose a ball is thrown straight up in the air
  with an initial velocity of 50 m/s. How high
  will the ball be after t seconds given that
• ht -16t2 v0t h0
• where ht is height after t seconds v0 is
  initial velocity and h0 is initial height