Learn Cobol - 9 Code Examples & CST Typing Practice Test

COBOL (Common Business-Oriented Language) is a high-level, English-like programming language designed for business applications, financial systems, batch processing, and large-scale enterprise data operations. Known for reliability, readability, and long-term stability.

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COBOL Counter and Theme Toggle COBOL Simple Addition COBOL Factorial COBOL Fibonacci Sequence COBOL Array Sum COBOL Max of Two Numbers COBOL Reverse String COBOL Even Numbers Filter COBOL String Concatenation

Learn COBOL with Real Code Examples

Updated Nov 19, 2025

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Code Sample Descriptions

COBOL Counter and Theme Toggle

       IDENTIFICATION DIVISION.
       PROGRAM-ID. CounterProgram.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 COUNT        PIC 9(4) VALUE 0.
       01 IS-DARK      PIC X VALUE 'N'.

       PROCEDURE DIVISION.
       DISPLAY 'Counter: ' COUNT
       DISPLAY 'Theme: ' IS-DARK

       ADD 1 TO COUNT
       DISPLAY 'Counter: ' COUNT

       MOVE 'Y' TO IS-DARK
       DISPLAY 'Theme: ' IS-DARK

       SUBTRACT 1 FROM COUNT
       DISPLAY 'Counter: ' COUNT

       MOVE 0 TO COUNT
       DISPLAY 'Counter: ' COUNT

       STOP RUN.

Demonstrates a simple counter with theme toggling using COBOL variables and console output.

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COBOL Simple Addition

       IDENTIFICATION DIVISION.
       PROGRAM-ID. AddProgram.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 A   PIC 9(4) VALUE 5.
       01 B   PIC 9(4) VALUE 3.
       01 SUM PIC 9(4) VALUE 0.

       PROCEDURE DIVISION.
       ADD A TO B GIVING SUM
       DISPLAY 'Sum: ' SUM
       STOP RUN.

Adds two numbers and displays the result.

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COBOL Factorial

       IDENTIFICATION DIVISION.
       PROGRAM-ID. FactorialProgram.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 N       PIC 9(2) VALUE 5.
       01 FACT    PIC 9(5) VALUE 1.
       01 COUNTER PIC 9(2) VALUE 1.

       PROCEDURE DIVISION.
       PERFORM VARYING COUNTER FROM 1 BY 1 UNTIL COUNTER > N
           MULTIPLY FACT BY COUNTER GIVING FACT
       END-PERFORM
       DISPLAY 'Factorial: ' FACT
       STOP RUN.

Calculates factorial of 5 using a loop.

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COBOL Fibonacci Sequence

       IDENTIFICATION DIVISION.
       PROGRAM-ID. FibonacciProgram.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 N      PIC 9(2) VALUE 10.
       01 A      PIC 9(5) VALUE 0.
       01 B      PIC 9(5) VALUE 1.
       01 TEMP   PIC 9(5) VALUE 0.
       01 COUNTER PIC 9(2) VALUE 1.

       PROCEDURE DIVISION.
       DISPLAY A
       PERFORM VARYING COUNTER FROM 2 BY 1 UNTIL COUNTER > N
           ADD A TO B GIVING TEMP
           DISPLAY B
           MOVE B TO A
           MOVE TEMP TO B
       END-PERFORM
       STOP RUN.

Generates first 10 Fibonacci numbers.

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COBOL Array Sum

       IDENTIFICATION DIVISION.
       PROGRAM-ID. ArraySum.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 NUMBERS.
          05 NUM PIC 9(2) OCCURS 5 TIMES VALUE 1 2 3 4 5.
       01 SUM PIC 9(3) VALUE 0.
       01 INDEX PIC 9(2) VALUE 1.

       PROCEDURE DIVISION.
       PERFORM VARYING INDEX FROM 1 BY 1 UNTIL INDEX > 5
           ADD NUM (INDEX) TO SUM
       END-PERFORM
       DISPLAY 'Sum: ' SUM
       STOP RUN.

Sum elements of an array.

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COBOL Max of Two Numbers

       IDENTIFICATION DIVISION.
       PROGRAM-ID. MaxProgram.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 A   PIC 9(4) VALUE 7.
       01 B   PIC 9(4) VALUE 10.
       01 MAX PIC 9(4) VALUE 0.

       PROCEDURE DIVISION.
       IF A > B THEN
           MOVE A TO MAX
       ELSE
           MOVE B TO MAX
       END-IF
       DISPLAY 'Max: ' MAX
       STOP RUN.

Finds the maximum of two numbers.

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COBOL Reverse String

       IDENTIFICATION DIVISION.
       PROGRAM-ID. ReverseString.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 STR PIC X(10) VALUE 'HELLO'.
       01 REV PIC X(10).
       01 INDEX1 PIC 9(2) VALUE 5.
       01 INDEX2 PIC 9(2) VALUE 1.

       PROCEDURE DIVISION.
       PERFORM VARYING INDEX2 FROM 1 BY 1 UNTIL INDEX2 > 5
           MOVE STR (INDEX1:1) TO REV (INDEX2:1)
           SUBTRACT 1 FROM INDEX1
       END-PERFORM
       DISPLAY 'Reversed: ' REV
       STOP RUN.

Reverses a string and displays it.

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COBOL Even Numbers Filter

       IDENTIFICATION DIVISION.
       PROGRAM-ID. EvenNumbers.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 NUMS.
          05 NUM PIC 9(2) OCCURS 10 TIMES VALUE 1 2 3 4 5 6 7 8 9 10.
       01 INDEX PIC 9(2) VALUE 1.

       PROCEDURE DIVISION.
       PERFORM VARYING INDEX FROM 1 BY 1 UNTIL INDEX > 10
           IF NUM (INDEX) MOD 2 = 0 THEN
               DISPLAY NUM (INDEX)
           END-IF
       END-PERFORM
       STOP RUN.

Displays even numbers from an array.

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COBOL String Concatenation

       IDENTIFICATION DIVISION.
       PROGRAM-ID. ConcatStrings.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 STR1 PIC X(5) VALUE 'HELLO'.
       01 STR2 PIC X(5) VALUE 'WORLD'.
       01 RESULT PIC X(10).

       PROCEDURE DIVISION.
       STRING STR1 DELIMITED BY SPACE
              STR2 DELIMITED BY SPACE
              INTO RESULT
       END-STRING
       DISPLAY 'Concatenated: ' RESULT
       STOP RUN.

Concatenates two strings and displays result.

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Frequently Asked Questions about Cobol

What is Cobol?

What are the primary use cases for Cobol?

Banking and financial transaction systems. Payroll and HR systems. Insurance policy and claims processing. Government mainframe workloads. Batch data processing. Large-scale enterprise reporting

What are the strengths of Cobol?

Highly readable and self-documenting. Rock-solid stability for mission-critical systems. Excellent for large-scale batch processing. Unmatched legacy compatibility. Decades of proven reliability in finance/government

What are the limitations of Cobol?

Verbose syntax compared to modern languages. Not suited for modern web/app development. Small pool of new COBOL developers. Mainframe ecosystem can be expensive. Limited abstraction mechanisms

How can I practice Cobol typing speed?

CodeSpeedTest offers 9+ real Cobol code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.

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Learn Cobol - 9 Code Examples & CST Typing Practice Test

Code Sample Descriptions

COBOL Counter and Theme Toggle

       IDENTIFICATION DIVISION.
       PROGRAM-ID. CounterProgram.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 COUNT        PIC 9(4) VALUE 0.
       01 IS-DARK      PIC X VALUE 'N'.

       PROCEDURE DIVISION.
       DISPLAY 'Counter: ' COUNT
       DISPLAY 'Theme: ' IS-DARK

       ADD 1 TO COUNT
       DISPLAY 'Counter: ' COUNT

       MOVE 'Y' TO IS-DARK
       DISPLAY 'Theme: ' IS-DARK

       SUBTRACT 1 FROM COUNT
       DISPLAY 'Counter: ' COUNT

       MOVE 0 TO COUNT
       DISPLAY 'Counter: ' COUNT

       STOP RUN.

Demonstrates a simple counter with theme toggling using COBOL variables and console output.

Let’s Try →

COBOL Simple Addition

       IDENTIFICATION DIVISION.
       PROGRAM-ID. AddProgram.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 A   PIC 9(4) VALUE 5.
       01 B   PIC 9(4) VALUE 3.
       01 SUM PIC 9(4) VALUE 0.

       PROCEDURE DIVISION.
       ADD A TO B GIVING SUM
       DISPLAY 'Sum: ' SUM
       STOP RUN.

Adds two numbers and displays the result.

Let’s Try →

COBOL Factorial

       IDENTIFICATION DIVISION.
       PROGRAM-ID. FactorialProgram.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 N       PIC 9(2) VALUE 5.
       01 FACT    PIC 9(5) VALUE 1.
       01 COUNTER PIC 9(2) VALUE 1.

       PROCEDURE DIVISION.
       PERFORM VARYING COUNTER FROM 1 BY 1 UNTIL COUNTER > N
           MULTIPLY FACT BY COUNTER GIVING FACT
       END-PERFORM
       DISPLAY 'Factorial: ' FACT
       STOP RUN.

Calculates factorial of 5 using a loop.

Let’s Try →

COBOL Fibonacci Sequence

       IDENTIFICATION DIVISION.
       PROGRAM-ID. FibonacciProgram.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 N      PIC 9(2) VALUE 10.
       01 A      PIC 9(5) VALUE 0.
       01 B      PIC 9(5) VALUE 1.
       01 TEMP   PIC 9(5) VALUE 0.
       01 COUNTER PIC 9(2) VALUE 1.

       PROCEDURE DIVISION.
       DISPLAY A
       PERFORM VARYING COUNTER FROM 2 BY 1 UNTIL COUNTER > N
           ADD A TO B GIVING TEMP
           DISPLAY B
           MOVE B TO A
           MOVE TEMP TO B
       END-PERFORM
       STOP RUN.

Generates first 10 Fibonacci numbers.

Let’s Try →

COBOL Array Sum

       IDENTIFICATION DIVISION.
       PROGRAM-ID. ArraySum.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 NUMBERS.
          05 NUM PIC 9(2) OCCURS 5 TIMES VALUE 1 2 3 4 5.
       01 SUM PIC 9(3) VALUE 0.
       01 INDEX PIC 9(2) VALUE 1.

       PROCEDURE DIVISION.
       PERFORM VARYING INDEX FROM 1 BY 1 UNTIL INDEX > 5
           ADD NUM (INDEX) TO SUM
       END-PERFORM
       DISPLAY 'Sum: ' SUM
       STOP RUN.

Sum elements of an array.

Let’s Try →

COBOL Max of Two Numbers

       IDENTIFICATION DIVISION.
       PROGRAM-ID. MaxProgram.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 A   PIC 9(4) VALUE 7.
       01 B   PIC 9(4) VALUE 10.
       01 MAX PIC 9(4) VALUE 0.

       PROCEDURE DIVISION.
       IF A > B THEN
           MOVE A TO MAX
       ELSE
           MOVE B TO MAX
       END-IF
       DISPLAY 'Max: ' MAX
       STOP RUN.

Finds the maximum of two numbers.

Let’s Try →

COBOL Reverse String

       IDENTIFICATION DIVISION.
       PROGRAM-ID. ReverseString.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 STR PIC X(10) VALUE 'HELLO'.
       01 REV PIC X(10).
       01 INDEX1 PIC 9(2) VALUE 5.
       01 INDEX2 PIC 9(2) VALUE 1.

       PROCEDURE DIVISION.
       PERFORM VARYING INDEX2 FROM 1 BY 1 UNTIL INDEX2 > 5
           MOVE STR (INDEX1:1) TO REV (INDEX2:1)
           SUBTRACT 1 FROM INDEX1
       END-PERFORM
       DISPLAY 'Reversed: ' REV
       STOP RUN.

Reverses a string and displays it.

Let’s Try →

COBOL Even Numbers Filter

       IDENTIFICATION DIVISION.
       PROGRAM-ID. EvenNumbers.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 NUMS.
          05 NUM PIC 9(2) OCCURS 10 TIMES VALUE 1 2 3 4 5 6 7 8 9 10.
       01 INDEX PIC 9(2) VALUE 1.

       PROCEDURE DIVISION.
       PERFORM VARYING INDEX FROM 1 BY 1 UNTIL INDEX > 10
           IF NUM (INDEX) MOD 2 = 0 THEN
               DISPLAY NUM (INDEX)
           END-IF
       END-PERFORM
       STOP RUN.

Displays even numbers from an array.

Let’s Try →

COBOL String Concatenation

       IDENTIFICATION DIVISION.
       PROGRAM-ID. ConcatStrings.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 STR1 PIC X(5) VALUE 'HELLO'.
       01 STR2 PIC X(5) VALUE 'WORLD'.
       01 RESULT PIC X(10).

       PROCEDURE DIVISION.
       STRING STR1 DELIMITED BY SPACE
              STR2 DELIMITED BY SPACE
              INTO RESULT
       END-STRING
       DISPLAY 'Concatenated: ' RESULT
       STOP RUN.

Concatenates two strings and displays result.

Let’s Try →

Frequently Asked Questions about Cobol

What is Cobol?

What are the primary use cases for Cobol?

Banking and financial transaction systems. Payroll and HR systems. Insurance policy and claims processing. Government mainframe workloads. Batch data processing. Large-scale enterprise reporting

What are the strengths of Cobol?

What are the limitations of Cobol?

Verbose syntax compared to modern languages. Not suited for modern web/app development. Small pool of new COBOL developers. Mainframe ecosystem can be expensive. Limited abstraction mechanisms

How can I practice Cobol typing speed?

CodeSpeedTest offers 9+ real Cobol code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.