7-1 chapter 7. basic arithmetic verbs options available with arithmetic verbs compute statement ...

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Chapter 7

Basic Arithmetic Verbs Options Available with Arithmetic Verbs COMPUTE Statement Signed Numbers in Arithmetic Operations Intrinsic Functions

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ADD, SUBTRACT, MULTIPLY, DIVIDE All require fields operated on to

◦ Have numeric PICTURE clauses◦ Contain numeric data when statements executed

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identifier-1ADD … TO identifier-2 ...

literal-1

identifier-1 or literal-1 added to identifier-2 Result stored in identifier-2

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Format 1

Assume X, Y and Z are numeric fieldsX = 5, Y = 3 and Z = 7

ADD Statement ResultAdd X To Y Y = 8Add X, 9 To Y Y = 17Add X, 6, Y To Z Z = 21

Identifiers preceding TO are unchanged Value of identifier after TO

◦ Used in ADD operation◦ Original value replaced with ADD result

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identifier-1ADD … GIVING identifier-

2 ... literal-1

Identifiers and literals preceding GIVING added together

Result stored in identifier-2

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Format 2


ADD Statement ResultAdd X, Y Giving Z Z = 8Add X, 10 Giving Y Y = 15Add X, 4, Y Giving Z Z = 12

Identifiers preceding GIVING are unchanged Value of identifier after GIVING

◦ Original value replaced with ADD result◦ May be report-item with edit symbols

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Several ADD operations can be done in single statement


ADD Statement ResultAdd X To Y, Z Y = 8, Z = 12Add X, 6 Giving Y, Z Y = 11, Z = 11

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Use ADD … TO when original contents of result operand ◦ Need to be included in operation ◦ But are not needed after operation

Use ADD … GIVING when◦ Original contents of all operands except result

field are to be retained

◦ ADD HOURS-WORKED TO WEEKLY-HOURS

◦ Vs. Giving

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identifier-1SUBTRACT … FROM identifier-2 ...

literal-1

identifier-1 or literal-1 subtracted from identifier-2


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Format 1

Assume A, B and C are numeric fields A = 6, B = 2 and C = 18

SUBTRACT Statement ResultSubtract A From C C = 12Subtract B, 5 From C C = 11Subtract B From A, C A = 4, C = 16

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identifier-1 identifier-2

SUBTRACT … FROM literal-1 literal-2

GIVING identifier-3 ...

identifier-1 or literal-1 subtracted from identifier-2 or literal-2


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Format 2

Assume A, B and C are numeric fields A = 6, B = 2 and C = 18

SUBTRACT Statement ResultSubtract B From A Giving C C = 4Subtract A From 15 Giving C C = 9Subtract A, 4 From C Giving B B = 8

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identifier-1MULTIPLY BY identifier-2 ...

literal-1

identifier-1 or literal-1 multiplied by identifier-2


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Format 1

Assume Q, R and S are numeric fields Q = 4, R = 7 and S = 5

MULTIPLY Statement ResultMultiply Q By R R = 28Multiply 10 By S S = 50 Multiply 2 By R, S R = 14, S = 10

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identifier-1 identifier-2MULTIPLY BY

literal-1 literal-2


identifier-1 or literal-1 multiplied by identifier-2 or literal-2


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Format 2

Assume Q, R and S are numeric fields Q = 4, R = 7 and S = 5

MULTIPLY Statement ResultMultiply Q By R Giving S S = 28Multiply Q By 3 Giving S S = 12Multiply 6 By Q Giving R, S R = 24

S = 24

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Only two operands can be multiplied using the MULTIPLY statement

To obtain product of 3 operands requires two instructions

To find Price x Qty x Discount

Multiply Price By Qty Giving WS-AmtMultiply Discount By WS-Amt

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identifier-1DIVIDE INTO identifier-2 ...

literal-1

identifier-1 or literal-1 divided into identifier-2 Result stored in identifier-2

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Format 1


DIVIDE Statement ResultDivide X Into Y Y = 6Divide 3 Into Y Y = 4 Divide 2 Into Y, Z Y = 6, Z = 4

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identifier-1 INTO identifier-2

DIVIDE literal-1 BY literal-2


identifier-1 or literal-1 divided into or by identifier-2 or literal-2


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Format 2


DIVIDE Statement ResultDivide X Into Y Giving Z Z = 6Divide Y By X Giving Z Z = 6Divide 16 By Z Giving X, Y X = 2

Y = 2

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Optional clause with DIVIDE used to store remainder of division

Assume Q and R have PICTUREs of 99

Divide 70 By 15 Giving Q Remainder R

Stores quotient 4 in Q and integer remainder 10 in R

What can this be used for??? Same as MOD

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Arithmetic result truncated if room to store all decimal positions not available◦ Result of 3.89 stored in field with PIC 9V9 as 3^8

Include ROUNDED to round result to PICTURE specification◦ Result of 3.89 stored as 3.9 if ROUNDED option

used◦ Its actually adding .5 then truncating

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01 Amt1 Pic 9V99 Value 2.25.01 Amt2 Pic 999.

Arithmetic statement Result Value Stored

Multiply .3 By Amt1 .675 Amt1 = 0^67

Multiply .3 By Amt1 Rounded .675 Amt1 = 0^68

Divide 150 By 9Giving Amt2 Rounded 16.66… Amt2 = 017

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Examples

Occurs when result value too large to be stored in result field

Result of this ADD statement is 1,075Add 350 To 725 Giving Num

If Num has PICTURE of 999, only 3 digits can be stored

High-order digits truncated so 075 stored in Num

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Any arithmetic statement may include one or both size error clauses

ON SIZE ERROR statement(s)◦ Specifies one or more statements to be executed

if overflow (size error) occurs NOT ON SIZE ERROR statement(s)

◦ Specifies one or more statements to be executed if overflow (size error) does not occur

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Add X To Y Giving ZOn Size Error Display ' Result too large'Not On Size Error Perform Calc-Para

End-Add

If sum of X and Y too large to store in Z, Display statement executed

If Z large enough for result, Calc-Para is performed

When using one or both clauses, use scope terminator to end arithmetic operation◦ END-ADD, END-SUBTRACT ◦ END-MULTIPLY, END-DIVIDE

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Ensure receiving field has PICTURE large enough to store result

Addition - define resultant field one position larger than largest field added

Subtraction - define resultant field as large as number being subtracted from◦ Assumes positive numbers◦ Assumes smaller subtracted from larger number

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Multiplication - define resultant field equal to sum of lengths of operands begin multiplied

Division - define resultant field equal to sum of number of digits in divisor and dividend

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General arithmetic statement using symbols in place of arithmetic verbs

Symbol Verb+ ADD- SUBTRACT* MULTIPLY/ DIVIDE** exponentiation

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arithmetic-exp-1

COMPUTE identifier-1 … = literal-1 identifier-2

Identifier to left of equal sign set to value of arithmetic-expression, literal or identifier on right of equal sign

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Format


COMPUTE Statement ResultCompute Z = X * Y Z = 36Compute X = Z - Y + 2 X = 10Compute X = Y X = 4Compute Z = Y ** 2 Z = 16

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Arithmetic expression may include any combination of symbols +, -, *, / or **

Order of operations

1. ( ) override rules 1-3, all operations in ( ) performed first

2. ** all exponentiation performed first3. * or / in order or appearance left to right4. + or - in order or appearance left to right

Same rules apply here as standard math

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COMPUTE Statement ResultCompute Z = Y / X + 3 Z = 6Compute Z = Y / (X + 3) Z = 2Compute Y = Z + X * 10 Y = 65Compute Y = Z * X / 10 Y = 3

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COMPUTE can include same optional clauses used with other arithmetic verbs

ROUNDED follows result field (identifier preceding equal sign)

If ON SIZE ERROR or NOT ON SIZE ERROR clauses used, include scope terminator END-COMPUTE

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Use S in PIC clause of result field if◦ Numbers used in calculation may be negative◦ Calculation may produce negative results

PIC clause without S assumed to be unsigned◦ If negative result stored in unsigned field, sign not

retained We discussed this already

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Built-in procedures to perform particular task like◦ Find square root of number◦ Convert letters to uppercase◦ Get current date

Looks like our compiler handles these because of Lab 2 with the NUMVAL function

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Find square root of X and place result in Y

Compute Y = Function Sqrt(X)

Value of X passed to function called Sqrt Code in function finds square root of X Result returned by Sqrt assigned to Y

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Example

Convert More-Data to uppercase

Move Function Upper-Case (More-Data) To Up-More-Data

If More-Data = "Yes", function Upper-Case returns value "YES"

Value "YES" moved to Up-More-Data

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Example

Output of function - result returned after function performs its task

Function returning alphanumeric result used in statements using alphanumeric data-items

Function returning numeric result can be used only in arithmetic expressions, of course

Page 283 – 288 has a list of several categorized by type

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ADD, SUBTRACT, MULTIPLY, and DIVIDE verbs ◦ format without GIVING

Receiving field is part of arithmetic May not be report-item

◦ with GIVING format Receiving field is not part of arithmetic May be report-item

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COMPUTE used for any combination of arithmetic operations

Order of evaluation of operators1. **2. * or / in sequence left to right3. + or - in sequence left to right4. ( ) override normal hierarchy rules

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ROUNDED can follow receiving field in any arithmetic verb

ON SIZE ERROR, NOT ON SIZE ERROR◦ Can be used with any arithmetic verb◦ Include scope terminator (e.g., END-ADD)

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Intrinsic functions added as COBOL extensions in 1989◦ Calendar◦ Numerical analysis◦ Statistical◦ Trigonometric◦ Financial◦ Character and String

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7-1 chapter 7. basic arithmetic verbs options available with arithmetic verbs compute statement ...

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giving identifier

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giving c c

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