Name: COBOL Coding Basics: Learn Mainframe Programming
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Created byProgLang MainSt.

Last updated 4/2026

English

What you'll learn

Write syntactically correct COBOL programs using the proper column layout and four-division structure
Declare and initialize variables using PIC clauses, level numbers, and the VALUE keyword
Perform arithmetic operations with ADD, SUBTRACT, MULTIPLY, DIVIDE, and COMPUTE
Format numeric output for business reports using edited picture clauses
Implement conditional logic with IF-ELSE, EVALUATE, and level 88 condition names
Build loops using PERFORM, PERFORM VARYING, and PERFORM UNTIL
Manipulate strings with STRING, UNSTRING, INSPECT, and reference modification
Create and process one-dimensional and two-dimensional tables with OCCURS
Organize programs into clean, modular paragraphs using PERFORM and PERFORM THRU
Apply professional techniques including REDEFINES, COPY, ROUNDED, and scope terminators

Course content

5 sections • 30 lectures • 5h 33m total length

The Four Divisions of a COBOL Program10:35
Explore the four mandatory divisions of every COBOL program — IDENTIFICATION, ENVIRONMENT, DATA, and PROCEDURE — and build a reusable program skeleton template.
DISPLAY and STOP RUN9:23
Write your first COBOL "Hello World" program using the DISPLAY statement for output and STOP RUN for clean program termination.
Writing Comments in COBOL2:11
Learn to document your COBOL code using asterisk comments in column 7, building a habit that becomes critical in large-scale production programs.
Using Periods and Sentence Structure11:54
Understand how periods act as statement terminators in COBOL and how misplaced periods cause subtle bugs, especially with conditional logic.

Declaring Variables with PIC12:12
Declare variables using the PICTURE clause (PIC) to define alphanumeric, numeric, and alphabetic fields with exact sizes in WORKING-STORAGE.
Level Numbers and Data Hierarchy10:56
Organize related data fields into hierarchies using level numbers 01 through 49, plus level 77 for standalone variables.
The MOVE Statement11:32
Assign values to variables with the MOVE statement and learn how COBOL automatically pads or truncates data to fit the receiving field's PIC definition.
Numeric Data and the VALUE Clause13:58
Initialize variables at declaration time using the VALUE clause and learn how COBOL handles signed numbers with PIC S9.
Basic Arithmetic with ADD and SUBTRACT12:47
Use COBOL's English-like ADD and SUBTRACT arithmetic verbs with the GIVING keyword to perform and store calculation results.
MULTIPLY, DIVIDE, and COMPUTE13:44
Perform multiplication and division with named verbs, then use COMPUTE for complex formulas using familiar math symbols like +, -, *, and /.
Edited Pictures for Formatted Output14:59
Format raw numbers into professional business output using edited PIC clauses with zero suppression, decimal points, commas, and currency symbols.

IF, ELSE, and END-IF11:03
Write conditional logic using IF, ELSE, and END-IF to make your COBOL programs respond to data values and execute different code paths.
Condition Names with Level 8811:11
Attach meaningful labels to specific variable values using level 88 condition names, making your IF statements read like plain English.
EVALUATE for Multi-Way Branching11:17
Replace long IF-ELSE chains with EVALUATE for clean multi-way branching using WHEN clauses and a WHEN OTHER default catch-all.
PERFORM for Simple Loops9:40
Execute a named paragraph a specific number of times using PERFORM with the TIMES keyword for simple counted repetition.
PERFORM VARYING for Counted Iteration9:51
Build classic for-loops with PERFORM VARYING that initialize, test, and increment a counter variable in a single statement.
PERFORM UNTIL with Inline Logic8:42
Write inline loops using PERFORM UNTIL with END-PERFORM, keeping the loop body in place without needing a separate paragraph.
Combining Conditions with AND and OR12:16
Combine multiple conditions in IF statements using AND, OR, NOT, and parentheses for nuanced multi-factor business logic decisions.

STRING and UNSTRING for Text Handling10:37
Concatenate text fields with STRING and split delimited data with UNSTRING — COBOL's primary tools for text manipulation and input parsing.
INSPECT for Counting and Replacing Characters11:42
Scan strings to count character occurrences with INSPECT TALLYING and replace specific characters with INSPECT REPLACING, without writing manual loops.
Reference Modification for Substrings12:06
Extract and modify substrings using reference modification syntax like WS-NAME(1:5) for precise character-level control over string data.
Defining Tables with OCCURS11:18
Create arrays in COBOL using the OCCURS clause, populate elements with subscript notation, and display table contents. Subscripts start at 1.
Looping Through Tables with PERFORM VARYING10:15
Iterate through OCCURS tables using PERFORM VARYING loops to populate and read back elements — the most common table-processing pattern in COBOL.
Two-Dimensional Tables with Nested OCCURS9:29
Build grid-like data structures by nesting OCCURS clauses, then populate and display them using nested PERFORM VARYING loops with two subscripts.

Organizing Logic with Paragraphs10:46
Define named paragraphs in the PROCEDURE DIVISION and call them with PERFORM to organize your program into reusable, single-responsibility code blocks.
PERFORM THRU for Paragraph Ranges10:53
Execute a consecutive range of paragraphs with a single PERFORM THRU statement, useful for logically ordered processing steps that always run together.
Using ACCEPT for User Input11:45
Read user input at runtime with the ACCEPT statement and retrieve system values like the current date and time using FROM DATE and FROM TIME.
Scope Terminators and Nested Statements11:24
Use explicit scope terminators like END-IF, END-PERFORM, and END-EVALUATE to safely nest control structures without ambiguous period-based termination.
The REDEFINES Clause12:47
Share physical memory between two variable definitions using REDEFINES to interpret the same bytes as different data structures, such as splitting a date field.
Handling Decimal Precision with ROUNDED12:21
Control decimal precision in arithmetic using the ROUNDED keyword instead of default truncation — critical for financial systems where fractions of a cent matter.

Requirements

Basic understanding of what programming is — you should know what variables, loops, and conditions mean conceptually
Comfort using a command line or terminal to run commands
Access to a COBOL compiler such as GnuCOBOL installed on your system
No prior COBOL experience required — this course starts from the very beginning

Description

This course contains the use of artificial intelligence.

COBOL has been quietly running the world’s most critical systems for over six decades, processing an estimated 95 percent of ATM transactions and 80 percent of in-person financial exchanges every single day. Despite being one of the oldest programming languages still in active use, the demand for COBOL developers has never been higher — and the supply has never been thinner. If you have ever wanted to learn a language that directly impacts billions of dollars in daily commerce and is practically synonymous with job security, this is your starting point.

This course takes you from writing your very first COBOL program all the way through advanced data handling and program organization techniques. You will begin with the fundamentals — the column layout, the four-division structure, DISPLAY output, and comments — then move into declaring and manipulating data using PIC clauses, level numbers, arithmetic verbs, and edited pictures for formatted output. From there, you will master control flow with IF statements, EVALUATE branching, PERFORM loops, compound conditions, and COBOL’s unique level 88 condition names. The course then dives into string manipulation with STRING, UNSTRING, and INSPECT, builds up your understanding of tables using OCCURS and nested subscripts, and finishes with professional techniques like paragraph-based organization, REDEFINES, copybooks, scope terminators, and decimal precision handling.

This course is designed for anyone with basic programming awareness who wants to add COBOL to their skill set — whether you are a developer looking to work with legacy systems, a computer science student exploring languages beyond the usual suspects, or a career changer targeting the lucrative mainframe job market. By the end, you will be able to write complete, well-structured COBOL programs that declare data, implement business logic, process collections, and follow the conventions used in real production environments.

What sets this course apart is its relentless focus on hands-on code. Every single lecture centers on a real COBOL code snippet that you can type, compile, and run. There are no abstract lectures, no rambling theory sessions, and no filler. You learn by doing, one concept at a time, building genuine fluency in a language that most programmers only read about. Enroll now and discover why COBOL is not just alive — it is essential.

Who this course is for:

Beginner programmers who want to learn COBOL as their first or second language
Software developers looking to transition into mainframe development or legacy system maintenance
Computer science students who want to expand their knowledge beyond modern web-focused languages
Career changers targeting the high-demand mainframe job market in banking, insurance, and government
IT professionals who need to read, understand, or modify existing COBOL codebases at their organization

What you'll learn

Explore related topics

Course content

Your First Lines of COBOL4 lectures • 34min

Working with Data in COBOL7 lectures • 1hr 30min

Control Flow and Decision Making7 lectures • 1hr 14min

Strings, Tables, and Data Structures6 lectures • 1hr 5min

Paragraphs, Program Structure, and Advanced Techniques6 lectures • 1hr 10min

Requirements

Description

Who this course is for: