1. 7-1 COBOL for the 21 st Century Nancy Stern Hofstra University Robert A. Stern Nassau Community College James P. Ley University of Wisconsin-Stout (Emeritus) John Wiley & Sons, Inc. 11th edition

2. 7-2 Computing in COBOL: The Arithmetic Verbs and Intrinsic Functions Chapter 7

3. 7-3 Chapter Objectives To familiarize you with Ways in which arithmetic may be performed in COBOL Formats and options available with arithmetic verbs

4. 7-4 Chapter Contents Basic Arithmetic Verbs Options Available with Arithmetic Verbs COMPUTE Statement Signed Numbers in Arithmetic Operations Intrinsic Functions

5. 7-5 Basic Arithmetic Verbs ADD, SUBTRACT, MULTIPLY, DIVIDE All require fields operated on to –Have numeric PICTURE clauses –Contain numeric data when statements executed

6. 7-6 ADD … TO Statement identifier-1 ADD… TO identifier-2... literal-1 identifier-1 or literal-1 added to identifier-2 Result stored in identifier-2 Format 1

7. 7-7 ADD … TO Examples Assume X, Y and Z are numeric fields X = 5, Y = 3 and Z = 7 ADD StatementResult Add X To YY = 8 Add X, 9 To YY = 17 Add X, 6, Y To ZZ = 21

8. 7-8 ADD … TO Statement Identifiers preceding TO are unchanged Value of identifier after TO –Used in ADD operation –Original value replaced with ADD result

9. 7-9 ADD … GIVING Statement identifier-1 ADD … GIVING identifier-2... literal-1 Identifiers and literals preceding GIVING added together Result stored in identifier-2 Format 2

10. 7-10 ADD … GIVING Examples Assume X, Y and Z are numeric fields X = 5, Y = 3 and Z = 7 ADD StatementResult Add X, Y Giving ZZ = 8 Add X, 10 Giving YY = 15 Add X, 4, Y Giving ZZ = 12

11. 7-11 ADD … GIVING Statement Identifiers preceding GIVING are unchanged Value of identifier after GIVING –Not part of ADD operation –Original value replaced with ADD result –May be report-item with edit symbols

12. 7-12 ADD … GIVING Statement TO may be included before last identifier or literal preceding GIVING For example: Add X, 4 To Y Giving Z –Adds values of X, 4 and Y together –Stores result in Z

13. 7-13 ADD Statement Comma followed by one space may be used to separate operands Result of ADD always placed in field(s) after TO or GIVING Result field must be data-name, not a literal

14. 7-14 Producing More Than One Sum Several ADD operations can be done in single statement Assume X, Y and Z are numeric fields X = 5, Y = 3 and Z = 7 ADD StatementResult Add X To Y, ZY = 8, Z = 12 Add X, 6 Giving Y, ZY = 11, Z = 11

15. 7-15 ADD … TO vs ADD … GIVING 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

16. 7-16 SUBTRACT Statement identifier-1 SUBTRACT … FROM identifier-2... literal-1 identifier-1 or literal-1 subtracted from identifier-2 Result stored in identifier-2 Format 1

17. 7-17 SUBTRACT Examples Assume A, B and C are numeric fields A = 6, B = 2 and C = 18 SUBTRACT Statement Result Subtract A From C C = 12 Subtract B, 5 From C C = 11 Subtract B From A, C A = 4, C = 16

18. 7-18 SUBTRACT Statement Rules All identifiers and literals must be numeric Data-name, not a literal, must follow FROM All fields, literals preceding FROM added together Sum subtracted from field after FROM Result stored in field after FROM

19. 7-19 SUBTRACT … GIVING Statement 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 Result stored in identifier-3 Format 2

20. 7-20 SUBTRACT … GIVING Examples Assume A, B and C are numeric fields A = 6, B = 2 and C = 18 SUBTRACT StatementResult Subtract B From A Giving C C = 4 Subtract A From 15 Giving C C = 9 Subtract A, 4 From C Giving B B = 8

21. 7-21 SUBTRACT … GIVING Rules All identifiers, literals before FROM must be numeric GIVING must be followed by data-name –May be numeric or report-item All fields, literals preceding FROM added together Sum subtracted from field after FROM Result stored in field after GIVING

22. 7-22 MULTIPLY Statement identifier-1 MULTIPLY BY identifier-2... literal-1 identifier-1 or literal-1 multiplied by identifier-2 Result stored in identifier-2 Format 1

23. 7-23 MULTIPLY Examples Assume Q, R and S are numeric fields Q = 4, R = 7 and S = 5 MULTIPLY StatementResult Multiply Q By R R = 28 Multiply 10 By S S = 50 Multiply 2 By R, S R = 14, S = 10

24. 7-24 MULTIPLY … GIVING Statement identifier-1 identifier-2 MULTIPLY BY literal-1 literal-2 GIVING identifier-3... identifier-1 or literal-1 multiplied by identifier-2 or literal-2 Result stored in identifier-3 Format 2

25. 7-25 MULTIPLY … GIVING Examples Assume Q, R and S are numeric fields Q = 4, R = 7 and S = 5 MULTIPLY StatementResult Multiply Q By R Giving SS = 28 Multiply Q By 3 Giving S S = 12 Multiply 6 By Q Giving R, S R = 24 S = 24

26. 7-26 MULTIPLY Statement Only two operands can be multiplied To obtain product of 3 operands requires two instructions To find Price x Qty x Discount Multiply Price By Qty Giving WS-Amt Multiply Discount By WS-Amt

27. 7-27 DIVIDE Statement identifier-1 DIVIDE INTO identifier-2... literal-1 identifier-1 or literal-1 divided into identifier-2 Result stored in identifier-2 Format 1

28. 7-28 DIVIDE Examples Assume X, Y and Z are numeric fields X = 2, Y = 12 and Z = 8 DIVIDE StatementResult Divide X Into Y Y = 6 Divide 3 Into Y Y = 4 Divide 2 Into Y, Z Y = 6, Z = 4

29. 7-29 DIVIDE … GIVING Statement identifier-1 INTO identifier-2 DIVIDE literal-1 BY literal-2 GIVING identifier-3... identifier-1 or literal-1 divided into or by identifier-2 or literal-2 Result stored in identifier-3 Format 2

30. 7-30 DIVIDE … GIVING Examples Assume X, Y and Z are numeric fields X = 2, Y = 12 and Z = 8 DIVIDE StatementResult Divide X Into Y Giving ZZ = 6 Divide Y By X Giving Z Z = 6 Divide 16 By Z Giving X, Y X = 2 Y = 2

31. 7-31 REMAINDER Clause 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

32. 7-32 ROUNDED Option 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

33. 7-33 ROUNDED Option 01 Amt1Pic 9V99Value 2.25. 01 Amt2Pic 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 9 Giving Amt2 Rounded16.66… Amt2 = 017 Examples

34. 7-34 Overflow or Size Error Occurs when result value too large to be stored in result field Result of this ADD statement is 1,075 Add 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

35. 7-35 Checking for Overflow 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

36. 7-36 SIZE ERROR Clause Example Add X To Y Giving Z On 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

37. 7-37 SIZE ERROR Clauses When using one or both clauses, use scope terminator to end arithmetic operation –END-ADD, END-SUBTRACT –END-MULTIPLY, END-DIVIDE

38. 7-38 Size of Receiving Fields 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

39. 7-39 Size of Receiving Fields 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

40. 7-40 COMPUTE Statement General arithmetic statement using symbols in place of arithmetic verbs SymbolVerb +ADD -SUBTRACT *MULTIPLY /DIVIDE **exponentiation

41. 7-41 COMPUTE Statement 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 Format

42. 7-42 COMPUTE Examples Assume X, Y and Z are numeric fields X = 9, Y = 4 and Z = 12 COMPUTE StatementResult Compute Z = X * YZ = 36 Compute X = Z - Y + 2 X = 10 Compute X = YX = 4 Compute Z = Y ** 2Z = 16

43. 7-43 Order of Evaluation Arithmetic expression may include any combination of symbols +, -, *, / or ** Order of operations 1.** all exponentiation performed first 2.* or / in order or appearance left to right 3.+ or - in order or appearance left to right 4.( ) override rules 1-3, all operations in ( ) performed first

44. 7-44 COMPUTE Examples Assume X, Y and Z are numeric fields X = 6, Y = 18 and Z = 5 COMPUTE StatementResult Compute Z = Y / X + 3 Z = 6 Compute Z = Y / (X + 3) Z = 2 Compute Y = Z + X * 10Y = 65 Compute Y = Z * X / 10Y = 3

45. 7-45 COMPUTE Statement 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

46. 7-46 Signed Numbers 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

47. 7-47 Intrinsic Functions Built-in procedures to perform particular task like –Find square root of number –Convert letters to uppercase –Get current date Approved as extensions to COBOL standard in 1989 Now included in many compilers

48. 7-48 Intrinsic Functions 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 Example

49. 7-49 Intrinsic Functions 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 Example

50. 7-50 Intrinsic Functions FUNCTION function-name (argument) Argument - input to function –May be numeric or alpha-numeric depending on function –Functions may have 0, 1 or more Format

51. 7-51 Intrinsic Functions 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

52. 7-52 COBOL 2008 Changes Spaces around arithmetic operators will no longer be required COMPUTE statement will yield same results on all compilers –Will make precision or number of decimal places in each intermediate calculation fixed

53. 7-53 Chapter Summary 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

54. 7-54 Chapter Summary COMPUTE used for any combination of arithmetic operations Order of evaluation of operators 1.** 2.* or / in sequence left to right 3.+ or - in sequence left to right 4.( ) override normal hierarchy rules

55. 7-55 Chapter Summary 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)

56. 7-56 Chapter Summary Intrinsic functions added as COBOL extensions in 1989 –Calendar –Numerical analysis –Statistical –Trigonometric –Financial –Character and String

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58. 7-58 Computing in COBOL: The Arithmetic Verbs and Intrinsic Functions Chapter 7