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

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

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

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

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

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

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

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

9. 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

10. 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

11. 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 Statement Result
Add X To Y, Z Y = 8, Z = 12
Add X, 6 Giving Y, Z Y = 11, Z = 11

12. 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
ADD HOURS-WORKED TO WEEKLY-HOURS
Vs. Giving

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

14. 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

15. SUBTRACT … GIVING Statement
identifier identifier-2
SUBTRACT … FROM
literal literal-2
GIVING identifier-3 ...
identifier-1 or literal-1 subtracted from identifier-2 or literal-2
Result stored in identifier-3
Format 2

16. SUBTRACT … GIVING Examples
Assume A, B and C are numeric fields A = 6, B = 2 and C = 18 SUBTRACT Statement Result 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

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

18. MULTIPLY Examples MULTIPLY Statement Result
Assume Q, R and S are numeric fields
Q = 4, R = 7 and S = 5
MULTIPLY Statement Result
Multiply Q By R R = 28
Multiply 10 By S S = 50
Multiply 2 By R, S R = 14, S = 10

19. 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

20. MULTIPLY … GIVING Examples
Assume Q, R and S are numeric fields Q = 4, R = 7 and S = 5 MULTIPLY Statement Result Multiply Q By R Giving S S = 28 Multiply Q By 3 Giving S S = 12 Multiply 6 By Q Giving R, S R = 24 S = 24

21. MULTIPLY Statement
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-Amt
Multiply Discount By WS-Amt

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

23. DIVIDE Examples
Assume X, Y and Z are numeric fields X = 2, Y = 12 and Z = 8 DIVIDE Statement Result Divide X Into Y Y = 6 Divide 3 Into Y Y = 4 Divide 2 Into Y, Z Y = 6, Z = 4

24. DIVIDE … GIVING Statement
Format 2
identifier INTO identifier-2
DIVIDE
literal 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

25. DIVIDE … GIVING Examples
Assume X, Y and Z are numeric fields X = 2, Y = 12 and Z = 8 DIVIDE Statement Result Divide X Into Y Giving Z Z = 6 Divide Y By X Giving Z Z = 6 Divide 16 By Z Giving X, Y X = 2 Y = 2

26. 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
What can this be used for???

27. 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
Actually adding .5 then truncating

28. ROUNDED Option 01 Amt1 Pic 9V99 Value 2.25. 01 Amt2 Pic 999. Examples
Arithmetic statement Result Value Stored
Multiply .3 By Amt Amt1 = 0^67
Multiply .3 By Amt1 Rounded Amt1 = 0^68
Divide 150 By 9 Giving Amt2 Rounded … Amt2 = 017

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

30. 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

31. 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
When using one or both clauses, use scope terminator to end arithmetic operation
END-ADD, END-SUBTRACT
END-MULTIPLY, END-DIVIDE

32. 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

33. 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

34. COMPUTE Statement
General arithmetic statement using symbols in place of arithmetic verbs
Symbol Verb
+ ADD
- SUBTRACT
* MULTIPLY
/ DIVIDE
** exponentiation

35. COMPUTE Statement arithmetic-exp-1 COMPUTE identifier-1 … = literal-1
Identifier to left of equal sign set to value of arithmetic-expression, literal or identifier on right of equal sign
Format

36. COMPUTE Examples
Assume X, Y and Z are numeric fields X = 9, Y = 4 and Z = 12 COMPUTE Statement Result Compute Z = X * Y Z = 36 Compute X = Z - Y + 2 X = 10 Compute X = Y X = 4 Compute Z = Y ** 2 Z = 16

37. Order of Evaluation 1. ( ) override rules 1-3, all operations
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 first
3. * or / in order or appearance left to right
4. + or - in order or appearance left to right
Same rules apply here as standard math

38. COMPUTE Examples
Assume X, Y and Z are numeric fields X = 6, Y = 18 and Z = 5 COMPUTE Statement Result Compute Z = Y / X + 3 Z = 6 Compute Z = Y / (X + 3) Z = 2 Compute Y = Z + X * 10 Y = 65 Compute Y = Z * X / 10 Y = 3

39. 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

40. 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
We discussed this already

41. 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
Not sure about ours, we’ll have to test it

42. Intrinsic Functions Find square root of X and place result in Y
Example
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

43. Intrinsic Functions Convert More-Data to uppercase
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

44. 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 arguments
Format

45. 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, of course
Page 283 – 288 has a list of several categorized by type

46. COBOL 2008 Changes
Spaces around arithmetic operators will no longer be required
So we should put spaces around each word and the parenthesis
COMPUTE statement will yield same results on all compilers
Will make precision or number of decimal places in each intermediate calculation fixed
This depends on when the answer is stored.

47. 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

48. 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

49. 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)

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