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E0001 Computers in E0001 Computers in EngineeringEngineering

Built in Functions

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General NotesGeneral Notes

Check when the first assignment is due! Have you thought about it? Although not due it should be completed by

now!!!! Assignments may be “posted”on the 4th

floor Z block

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What is the outcome?What is the outcome?

READ studnumber, names$

DATA 12345, “smith”

total$ = “6”

PRINT total$ + 4

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Readings and ExercisesReadings and Exercises

Schneider Section 3.4 p 72-78 Schneider Practice Problems 3.4 p 78;

programming problems #’s 57, 60, 62, 66, 68

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Rem statementsRem statements

Rem short for REMARK used for adding comments to code useful for the programmer, not the user non executable line Two ways of adding comments

– REM– ‘

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ExamplesExamples

REM this line is a comment

REM This program will calculate….

REM This program was written by….

INPUT r,b,h ‘radius, base, height

READ n$, no$ ‘name, number

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Numeric FunctionsNumeric Functions

covers common numeric and trigonometric terms– square root - SQR(x)– SIN(angle), COS(angle), TAN(angle)

BEWARE - (angle) must be in RADIANS

– LOG (x) see handout for more examples

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Examples of Numeric Examples of Numeric FunctionsFunctions

SQR (x) - square root of x where x is– variable - given a value by the program or the

user– arithmetic operation - (6-4)/360*12

ABS - absolute value– ABS(-3) = 3; ABS(7) = 7– ABS(SQR(CINT(x)))

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String FunctionsString Functions

allows examining strings or parts; combining strings

allows string comparisons using <, >, = (relational operators)

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Examples of String FunctionsExamples of String Functions

LEN(s) - s is known as the argument– returns the length of the argument i.e. the

number of characters contained in the argument– blanks are counted as characters– LEN(“John and Mary”) = 13– Z$ = “John and Mary”: LEN(Z$) = 13– IF LEN(Z$) = 20 THEN PRINT “HELLO”

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LEFT$(x$, n) - x$ is any string; n is an integer from 0 to LEN(x$)– x$ = “John and Mary”– PRINT LEFT$(x$,4) - gives the output John

see also MID$(x$,n,m) and RIGHT$(x$,n) LCASE$(X$); UCASE$(X$);

INSTR(n,X$,Y$) VAL(X$) - converts a string whose contents

represent a number to its numerical form.– ignores leading blanks– converts a string up to its first nonnumerical

character into its numerical value.

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Built-in FunctionsBuilt-in Functions

prewritten “subroutine” that does one operation

returns ONE value only designed to manipulate both numerical and

string data cover common calculations

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The period P of a pendulum of length L and maximum displacement angle is given by the formula

P =

write a program that requests as input the length and maximum angle of displacement, and displays the period of the pendulum

ProblemProblem

L/ g(11

4sin (

2))2

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TutorialTutorial

1. What will be the contents of x after the following statement is executed?

LET x = SQR((9 + 7) / ( 4 * 2) + 2)

2. Suppose num = 123.4567. What is the output?

LET num = INT(100 * num + .5) / 100

PRINT num

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3. What output is generated by the following statements (show the output EXACTLY as it would appear on the screen)? PRINT SQR (3^2 + 4^2) PRINT MID$ ("Milkshake", 5, 5) PRINT UCASE$ ("123jump")

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shake

123JUMP try this for yourself

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4. The following statements are valid. (T/F)

LET H$ = "Hello"

LET a$ = INSTR(H$, 3)

5. Given the data in the variable y$ shown below, which of the following statements will assign the value ALL to x$?

LET y$ = "WHEN ALL ELSE FAILS, READ THE DIRECTIONS"

(a) LET x$ = MID$(y$, 6, 3)

(b) LET x$ = INSTR(6, y$, "ALL")

(c) LET x$ = LEFT$(y$, 3)

(d) LET x$ = MIDDLE$(y$, 6, 3)

(e) LET x$ = RIGHT$(y$, 8)

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6. What will be displayed when the following program is executed?

LET a$ = "THE WHOLE"

LET b$ = "PART"

LET c$ = MID$(a$, SQR(4), LEN(b$))

PRINT c$

END

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The EndThe End

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Now change the program to Now change the program to include INPUT statementsinclude INPUT statements

DIM radius AS integer

DIM pi AS double

DIM circ AS double

radius = 3.2

pi = 22/7

circ = 2*pi*radius

PRINT radius,pi,circ

DIM radius AS integer, pi AS double, circ AS double

pi = 22/7

INPUT radius

circ = 2*pi*radius

PRINT”radius = “;radius

PRINT”pi = “;pi

PRINT “circumference is“;circ