# Language Proposal

### 1. Hello World

- source used: [Cobol Emulator](https://www.jdoodle.com/execute-cobol-online)
- display the text "Hello World!" in the terminal
- https://www.tutorialspoint.com/cobol/cobol_program_structure.htm this website has useful information about the structure of the cobol language
- the Identification Division is mandatory for all programs and sub divisions have unique sentences within them and determine what is done with variables or IO in this example

  #### Input

        there is no input for this example

  #### Output

        the string "Hello World!" is sent to output via the included DISPLAY function

### 2. Quadratic Function

- Code altered from [Marco Biagini](https://www.quora.com/What-is-a-COBOL-program-that-will-solve-a-quadratic-equation)
- Solves a quadratic equation of the form **ax^2 + bx + c = 0**

  #### Input

      Coefficients are a fixed value with a = 1, b = 5, c = 6

  #### Output

      EQUATION: (1x^2) + 5x + 6 = 0

      The equation has two distinct real roots:
      Root 1: -02.00
      Root 2: -03.00

### 3. Integer Sort

- Code altered from [Wikibooks]https://en.wikibooks.org/wiki/Algorithm_Implementation/Sorting/Bubble_sort#COBOL

- Uses bubble sort to sort an array of integers.
  #### Input
      An array of integers
  #### Output
      The array sorted in ascending order

### 4. Language Features

- #### Identifiers

  All variables are declared within DATA DIVISION. Variable names accept letters(A-Z), digits(0-9), and hyphens(-). In the syntax of:

        <level-number> <variable-name>
            [PIC/PICTURE <data-type(variable-length>)]
            [VALUE <literal-value>]

  Statements in [ ] are optional. Example:

        01 INT-VAR      PIC 9(03 VALUE 123).

- #### Special words

  - Note: Keywords are not case sensitive but good practice is to only use uppercase
  - Division statements divide the structure of the code. Some examples are PROGRAM-ID, DATA DIVISION, WORKING STORAGE DIVISION, PROCEDURE DIVISION, and STOP RUN.
  - DISPLAY outputs data to user
  - MOVE sends data from one variable to another
  - ACCEPT allows for user input to go into a variable
  - Supports boolean values TRUE and FALSE

- #### Literal

        *> This is a comment in COBOL


  Non-numeric

            DISPLAY "This is a string in COBOL".
            DISPLAY 'This is a string in COBOL'.

  Numeric

            Digits 0 - 9
            Positive numbers: +10
            Negative numbers: -10
            Decimal: 10.00

- #### Math Operators

  Supports additon (+), subraction (-), multiplication (\*), and division (/) and exponentation (\*\*). Equations begin with COMPUTE.

            COMPUTE total = 1 + 2

- #### Relational Operators

  Supports =, >, <, >=, <=, NOT =

            IF a > b

- #### Delimiters

  Section headers and verb statements should end with a separator period (.)

            PROCEDURE DIVISION.
                MOVE "Hello" TO VAR1.

  Commas (,) can separate two variables

            ADD 3 TO VAR1, VAR2.

- #### Lists

  Supports arrays (known in COBOL as tables). Declared in DATA DIVISION. In the syntax of:

        01 <table-name>.
          02 <variable-name>    [PIC <data-type(length1)>]
                                OCCURS <int1> [TO <int2>] TIMES
                                [DEPENDING ON]
                                [DESCENDING|ASCENDING KEY IS <key_var>]
                                [INDEXED BY <index_name>]

  Statements in [ ] are optional. Example:

        01  Students
            03 Student-grades  PIC 9(03) OCCURS 6 TIMES.

- #### Loops

  Loops begin with a PERFORM statement and end with END-PERFORM. Note that a separator period (.) should not used within a PERFORM block.

            PERFORM <conditional statement>
                <statements-block>
            END-PERFORM.

- #### Branching
  Uses IF/END-IF and ELSE statements and nested statements. Note that a separator period (.) should not used within an IF statement.
            IF <condition>
                DISPLAY "Option 1"
            ELSE
                DISPLAY "Option 2"
            END-IF.

`Language Feature Sources`

- [tutorialspoint.com](https://www.tutorialspoint.com/cobol/cobol_basic_syntax.htm)

- [mainframestechhelp.com](https://www.mainframestechhelp.com/tutorials/cobol/)