Chapter 9 Exercises: String Handling and Character Manipulation

Tier 1: Fundamentals (Exercises 1-8)

These exercises cover basic usage of STRING, UNSTRING, INSPECT, and reference modification. If you are new to COBOL string handling, start here.

Exercise 1: Name Concatenation

Write a COBOL paragraph that takes the following fields and produces a formatted full name in "LAST, FIRST MIDDLE" format:

01  WS-FIRST   PIC X(15) VALUE "JANE".
01  WS-MIDDLE  PIC X(15) VALUE "MARIE".
01  WS-LAST    PIC X(20) VALUE "ROBERTSON".
01  WS-RESULT  PIC X(50).

Expected output: "ROBERTSON, JANE MARIE"

Use the STRING statement with appropriate DELIMITED BY clauses. Do not include trailing spaces from any source field.

Exercise 2: Date Reformatting

Given a date in YYYYMMDD format, produce the date in MM/DD/YYYY format using reference modification and STRING:

01  WS-DATE-IN   PIC X(08) VALUE "20240725".
01  WS-DATE-OUT  PIC X(10).

Expected output: "07/25/2024"

Exercise 3: CSV Field Counting

Write code that parses the following CSV string and counts the total number of fields using UNSTRING with TALLYING IN:

01  WS-CSV  PIC X(80)
    VALUE "RED,GREEN,BLUE,YELLOW,ORANGE,PURPLE,BROWN".

Display each field and the total field count.

Expected output: 7 fields parsed.

Exercise 4: Character Counting with INSPECT

Using INSPECT TALLYING, count the following in the string "PROGRAMMING IN COBOL IS POWERFUL":

  1. The number of spaces
  2. The number of occurrences of the letter "O"
  3. The total number of vowels (A, E, I, O, U)

Display each count.

Exercise 5: Vowels vs. Consonants

Extend Exercise 4 to calculate the number of consonants (non-vowel, non-space alphabetic characters). Display the counts for vowels, consonants, and spaces.

Hint: Total alphabetic characters minus vowels equals consonants.

Exercise 6: Leading Zero Removal

Write code using INSPECT REPLACING LEADING to convert "00000125.50" to " 125.50" (replace leading zeros with spaces):

01  WS-AMOUNT  PIC X(11) VALUE "00000125.50".

Exercise 7: Case Conversion with INSPECT CONVERTING

Using INSPECT CONVERTING (not intrinsic functions), convert the string "Hello World From COBOL" to all uppercase. Display the result.

Exercise 8: Phone Number Formatting

Given a raw phone number input that may contain parentheses, spaces, and hyphens, extract only the digits and reformat as NNN-NNN-NNNN:

01  WS-RAW-PHONE  PIC X(14) VALUE "(312) 555-1234".

Expected output: "312-555-1234"

Use reference modification to iterate through characters and build the clean number.

Tier 2: Intermediate (Exercises 9-16)

These exercises require combining multiple string operations and handling edge cases.

Exercise 9: Pipe-Delimited Record Builder

Write a program that takes the following fields and builds a pipe-delimited output record. Use the STRING statement with a delimiter stored in a variable:

01  WS-EMP-ID      PIC X(06) VALUE "E10042".
01  WS-EMP-NAME    PIC X(20) VALUE "MARTINEZ, CARLOS".
01  WS-EMP-DEPT    PIC X(10) VALUE "FINANCE".
01  WS-EMP-SALARY  PIC 9(6)V99 VALUE 72500.00.

Expected output: "E10042|MARTINEZ, CARLOS|FINANCE|72500.00"

Exercise 10: Multi-Delimiter Parsing

Parse the following record that uses both commas and pipes as delimiters. Use UNSTRING with OR and capture the delimiter used for each field with DELIMITER IN:

01  WS-MIXED  PIC X(60)
    VALUE "ACCT-001|SAVINGS,2500.00|2024-01-15".

Display each field and the delimiter that followed it.

Exercise 11: Word Counter

Write a paragraph that counts the number of words in a string. A word is defined as a sequence of non-space characters separated by one or more spaces:

01  WS-TEXT  PIC X(60)
    VALUE "  THE   QUICK  BROWN   FOX  JUMPED  ".

Expected output: "Word count: 5"

Hint: Use UNSTRING with DELIMITED BY ALL SPACES and TALLYING IN, or implement a character-by-character loop.

Exercise 12: Search and Replace

Implement a search-and-replace operation that replaces ALL occurrences of "CAT" with "DOG" in the following string:

01  WS-INPUT  PIC X(60)
    VALUE "THE CAT SAT ON THE MAT WITH THE CAT".

Expected output: "THE DOG SAT ON THE MAT WITH THE DOG"

Since the search and replacement strings are the same length, you may use either INSPECT REPLACING ALL or a loop with reference modification.

Exercise 13: SSN Masking

Write code that masks all but the last 4 digits of a Social Security Number:

01  WS-SSN  PIC X(11) VALUE "123-45-6789".

Expected output: "***-**-6789"

Use INSPECT REPLACING CHARACTERS with BEFORE INITIAL to mask the first part.

Exercise 14: Address Line Builder

Build a formatted two-line address from the following components. Handle the case where the unit number might be empty:

01  WS-STREET   PIC X(30) VALUE "456 ELM BOULEVARD".
01  WS-UNIT     PIC X(10) VALUE "SUITE 200".
01  WS-CITY     PIC X(20) VALUE "CHICAGO".
01  WS-STATE    PIC X(02) VALUE "IL".
01  WS-ZIP      PIC X(10) VALUE "60601-3456".

Expected output:

456 ELM BOULEVARD, SUITE 200
CHICAGO, IL  60601-3456

If WS-UNIT is spaces, the first line should be just the street address without a trailing comma.

Exercise 15: Extract Initials

Write a program that extracts the first letter of each word in a full name and formats them as initials with periods:

01  WS-NAME  PIC X(40) VALUE "JOHN MICHAEL ROBERT SMITH".

Expected output: "J.M.R.S."

Exercise 16: Numeric Field Validation

Write a validation routine using INSPECT TALLYING that checks whether a given field contains a valid dollar amount (digits, at most one decimal point, at most one leading negative sign):

01  WS-AMOUNT-1  PIC X(12) VALUE "12345.67".
01  WS-AMOUNT-2  PIC X(12) VALUE "123.45.67".
01  WS-AMOUNT-3  PIC X(12) VALUE "-500.00".
01  WS-AMOUNT-4  PIC X(12) VALUE "12A45.00".

Display whether each amount is valid or invalid and the reason.

Tier 3: Applied (Exercises 17-24)

These exercises involve realistic data processing scenarios combining multiple techniques.

Exercise 17: CSV Record Validator

Write a program that validates CSV records containing employee data. Each record should have exactly 5 comma-separated fields:

EMP-ID,LAST-NAME,FIRST-NAME,DEPARTMENT,SALARY

Validate: - EMP-ID is 6 characters starting with "E" - LAST-NAME and FIRST-NAME are not empty - DEPARTMENT is one of: IT, HR, FINANCE, SALES, OPS - SALARY is a valid numeric value greater than 0

Test with at least 5 records, including 2 that fail validation. Display valid records in a formatted report and list errors for invalid records.

Exercise 18: Email Address Validation

Write a validation routine for email addresses. Check: - Exactly one "@" symbol - At least one "." after the "@" - Non-empty local part (before @) - Non-empty domain part (after @)

Test with these inputs:

user@company.com       (valid)
user.name@dept.co.uk   (valid)
@company.com           (invalid - empty local)
user@                  (invalid - empty domain)
user@@company.com      (invalid - two @)
user.company.com       (invalid - no @)

Exercise 19: Fixed-Format to CSV Converter

Write a program that reads fixed-format records and converts them to CSV format. The input layout is:

Positions 1-5:   Account Number (numeric)
Positions 6-25:  Customer Name
Positions 26-45: Street Address
Positions 46-60: City
Positions 61-62: State
Positions 63-67: ZIP Code

Create at least 4 sample records in WORKING-STORAGE and produce CSV output. Trim trailing spaces from each field in the CSV output.

Exercise 20: String Compression

Write a routine that removes all extra spaces from a string, leaving only single spaces between words:

01  WS-INPUT  PIC X(60)
    VALUE "  THE   QUICK   BROWN   FOX   ".

Expected output: "THE QUICK BROWN FOX"

Exercise 21: Title Case Conversion

Convert a string to Title Case (first letter of each word uppercase, rest lowercase):

01  WS-INPUT  PIC X(40) VALUE "the quick brown fox jumps".

Expected output: "The Quick Brown Fox Jumps"

Use a combination of FUNCTION LOWER-CASE, FUNCTION UPPER-CASE, and reference modification.

Exercise 22: Date Validation and Formatting

Write a comprehensive date parser that accepts dates in multiple formats and converts them all to ISO format (YYYY-MM-DD):

  • MM/DD/YYYY (e.g., 12/25/2024)
  • DD-MON-YYYY (e.g., 25-DEC-2024)
  • YYYYMMDD (e.g., 20241225)

Validate the date components (month 1-12, day 1-31). Display the original format detected and the ISO output.

Exercise 23: Report Header Builder

Create a reusable paragraph that builds a centered report header. Given a title string and a line width (80 characters), center the title and surround it with a border:

================================================================================
                        QUARTERLY FINANCIAL REPORT
================================================================================

Calculate the padding dynamically based on the logical length of the title.

Exercise 24: Multi-Line Address Parser

Parse a single-line address string into components. The input may be in any of these formats:

"123 MAIN ST, APT 4B, SPRINGFIELD, IL 62701"
"456 OAK AVE, PORTLAND, OR 97201"
"789 PINE RD, SUITE 100, NEW YORK, NY 10001-2345"

Parse into: Street, Unit (optional), City, State, ZIP. Handle the optional unit and optional ZIP+4 extension.

Tier 4: Integration (Exercises 25-32)

These exercises require building more complete programs that integrate string handling with other COBOL features.

Exercise 25: Fixed-Width Report Line Builder

Build a report line generator that places values at specific column positions:

Column Width Field
1-20 20 Employee Name
22-31 10 Department
33-48 16 Salary (formatted with $ and commas)
50-59 10 Hire Date (MM/DD/YYYY)

Generate a header row and at least 5 data rows. Use STRING with WITH POINTER for column alignment.

Exercise 26: Data Cleansing Pipeline

Write a program that processes "dirty" input records through a series of cleansing steps:

  1. Convert to uppercase
  2. Replace all tab characters (if any) with spaces
  3. Compress multiple spaces to single spaces
  4. Trim leading and trailing spaces
  5. Validate that required fields are not empty
  6. Standardize date formats to YYYY-MM-DD

Process at least 5 sample records and display before/after results.

Exercise 27: Name Formatter

Write a program that accepts names in various formats and standardizes them all to "LASTNAME, FIRSTNAME M." format:

  • "John Q. Smith" -> "SMITH, JOHN Q."
  • "SMITH, JOHN" -> "SMITH, JOHN"
  • "mary jane watson" -> "WATSON, MARY J."
  • "DR. JAMES WILSON" -> "WILSON, JAMES (DR.)"

Handle at least 6 different name format variations.

Exercise 28: Simple Template Engine

Create a template expansion system. Given a template string with placeholders marked by {FIELD-NAME}, replace each placeholder with actual values:

Template: "Dear {FIRST-NAME}, your account {ACCT-NUM} has
a balance of {BALANCE}."

Process the template for at least 3 different sets of values.

Exercise 29: Log Message Parser

Parse log messages in the following format and extract components:

2024-03-15 14:30:45 [ERROR] Module: ACCTPROC - Invalid account number: 99999
2024-03-15 14:30:46 [INFO]  Module: BATCHCTL - Batch 42 started
2024-03-15 14:31:02 [WARN]  Module: ACCTPROC - Balance below threshold: $50.00

Extract: Date, Time, Severity, Module, Message. Count the number of each severity level.

Exercise 30: Check Digit Calculator

Implement the Luhn algorithm for validating credit card numbers. Given a card number as a string:

  1. Parse the digits from the string (removing any spaces or hyphens)
  2. Apply the Luhn algorithm
  3. Display whether the number is valid

Test with: - "4539 1488 0343 6467" (valid) - "1234 5678 9012 3456" (invalid)

Exercise 31: Encoded Record Processor

Write a program that processes records where certain fields are encoded. The encoding scheme is:

  • Letters are shifted by 3 positions (A->D, B->E, ..., X->A, Y->B, Z->C)
  • Digits remain unchanged
  • Special characters remain unchanged

Decode 3 sample records and display the original and decoded versions.

Exercise 32: Report Formatter with Word Wrap

Write a paragraph that takes a long text string and formats it into multiple lines of a specified maximum width (e.g., 40 characters) without breaking words:

01  WS-LONG-TEXT  PIC X(200) VALUE
    "THE QUICK BROWN FOX JUMPED OVER THE LAZY DOG "
    & "AND THEN RAN ALL THE WAY HOME TO REST".

Display the text wrapped at 40 characters per line. Break only at spaces.

Tier 5: Challenge (Exercises 33-38)

These are advanced exercises that require creative problem-solving and deep understanding of COBOL string handling.

Exercise 33: CSV Parser with Quoted Fields

Implement a CSV parser that correctly handles quoted fields. In standard CSV, fields may be enclosed in double quotes, allowing commas within a field:

"Smith, John",ACCT-001,"1,500.00",2024-03-15

This should parse as 4 fields: 1. Smith, John 2. ACCT-001 3. 1,500.00 4. 2024-03-15

Handle escaped quotes within quoted fields ("" represents a literal ").

Exercise 34: Soundex Algorithm

Implement the Soundex algorithm, which converts a name to a phonetic code. The algorithm:

  1. Keep the first letter
  2. Replace consonants with digits (B,F,P,V=1; C,G,J,K,Q,S,X,Z=2; D,T=3; L=4; M,N=5; R=6)
  3. Remove adjacent duplicate digits
  4. Remove vowels (A, E, I, O, U, H, W, Y)
  5. Pad or truncate to exactly 4 characters

Test with: SMITH (S530), JOHNSON (J525), WILLIAMS (W452).

Exercise 35: Data Migration Converter

Write a complete data migration program that:

  1. Reads 10 legacy fixed-format customer records
  2. Parses name (handling "LAST, FIRST" and "FIRST LAST" formats)
  3. Standardizes address components
  4. Validates all fields
  5. Produces a new fixed-format record with a different layout
  6. Generates a migration report with record counts, error counts, and a list of records that failed validation

Exercise 36: Expression Tokenizer

Write a simple tokenizer that breaks a mathematical expression string into tokens:

"(125 + 37) * 42 / 7 - 3"

Identify each token as: NUMBER, OPERATOR (+, -, *, /), or PARENTHESIS. Display the token list.

Exercise 37: Multi-Record Address Standardizer

Write a program that standardizes address abbreviations using a translation table:

Abbreviation Standard
ST STREET
AVE AVENUE
BLVD BOULEVARD
DR DRIVE
LN LANE
CT COURT
RD ROAD
APT APARTMENT
STE SUITE

Process 6 addresses, expanding abbreviations to their full forms. Handle abbreviations that appear at the end of a word or followed by a period.

Exercise 38: COBOL String Library

Create a COBOL program that implements a reusable set of string utility paragraphs:

  1. LEFT-PAD -- Pad a string on the left with a specified character to a specified length
  2. RIGHT-PAD -- Pad a string on the right
  3. CENTER -- Center a string within a specified width
  4. CONTAINS -- Check if a string contains a substring (return position or 0)
  5. STARTS-WITH -- Check if a string starts with a given prefix
  6. ENDS-WITH -- Check if a string ends with a given suffix
  7. REPLACE-ALL -- Replace all occurrences of a substring (handles different-length replacements)
  8. SPLIT-COUNT -- Count the number of delimited fields in a string

Write test cases for each utility paragraph demonstrating both normal and edge cases.

Solution Notes

Selected solutions for exercises 1, 3, 5, 8, 12, 15, 18, 21, and 25 are provided in code/exercise-solutions.cob. These solutions demonstrate proper COBOL coding style, error handling, and documentation.

For exercises not included in the solutions file, consider these approaches: - Start by identifying which string operation (STRING, UNSTRING, INSPECT, reference modification) is most appropriate - Initialize all receiving fields and counters before use - Always code ON OVERFLOW handlers - Test with boundary cases: empty fields, maximum-length data, and special characters