Learn JOVIAL with Real Code Examples

PROGRAM CounterTheme;

INTEGER COUNT := 0;
BOOLEAN ISDARK := FALSE;

PROCEDURE UPDATEUI;
BEGIN
    PUT('Counter: ' || COUNT);
    IF ISDARK THEN
        PUT('Theme: Dark');
    ELSE
        PUT('Theme: Light');
    END;
END UPDATEUI;

PROCEDURE INCREMENT;
BEGIN
    COUNT := COUNT + 1;
    CALL UPDATEUI;
END INCREMENT;

PROCEDURE DECREMENT;
BEGIN
    COUNT := COUNT - 1;
    CALL UPDATEUI;
END DECREMENT;

PROCEDURE RESET;
BEGIN
    COUNT := 0;
    CALL UPDATEUI;
END RESET;

PROCEDURE TOGGLETHEME;
BEGIN
    ISDARK := NOT ISDARK;
    CALL UPDATEUI;
END TOGGLETHEME;

BEGIN
    CALL UPDATEUI;
    CALL INCREMENT;
    CALL INCREMENT;
    CALL TOGGLETHEME;
    CALL DECREMENT;
    CALL RESET;
END CounterTheme;

Demonstrates a simple counter with theme toggling using JOVIAL variables and procedures.

PROGRAM RandomNumbers;
INTEGER I;
INTEGER NUM;
FOR I := 1 TO 3;
BEGIN
    NUM := RANDOM(100) + 1;
    PUT('Random ' || I || ': ' || NUM);
END;

Generates random numbers between 1 and 100 and prints them.

PROGRAM TodoList;
INTEGER COUNT := 0;
CHARACTER TODOS(10,20);

PROCEDURE ADD(TASK);
BEGIN
    TODOS(COUNT) := TASK;
    COUNT := COUNT + 1;
    PUT('Todos count: ' || COUNT);
END ADD;

PROCEDURE REMOVE(IDX);
INTEGER I;
BEGIN
    FOR I := IDX TO COUNT-2 DO
        TODOS(I) := TODOS(I+1);
    END;
    COUNT := COUNT - 1;
END REMOVE;

BEGIN
    CALL ADD('Buy milk');
    CALL ADD('Write JOVIAL code');
    CALL REMOVE(0);
END TodoList;

Maintains a simple todo list with add and remove functionality.

PROGRAM DiceRoller;
INTEGER I;
INTEGER ROLL;
FOR I := 1 TO 3;
BEGIN
    ROLL := RANDOM(6) + 1;
    PUT('Roll ' || I || ': ' || ROLL);
END;

Rolls a six-sided dice three times.

PROGRAM Countdown;
INTEGER COUNT := 5;
WHILE COUNT >= 0 DO
BEGIN
    PUT('Countdown: ' || COUNT);
    COUNT := COUNT - 1;
END;
PUT('Done!');

Counts down from 5 to 0.

PROGRAM PrimeCheck;
INTEGER NUMS(3) := (7,10,13);
INTEGER N,I;
BOOLEAN ISPRIME;

FOR N := 1 TO 3 DO
BEGIN
    ISPRIME := TRUE;
    FOR I := 2 TO NUMS(N)-1 DO
        IF NUMS(N) MOD I = 0 THEN ISPRIME := FALSE;
    END;
    PUT(NUMS(N) || IF ISPRIME THEN ' is Prime' ELSE ' is Not Prime');
END;

Checks if numbers are prime.

PROGRAM TempConvert;
REAL C,F;
C := 25;
F := C*9/5+32;
PUT('25°C = ' || F || '°F');
F := 77;
C := (F-32)*5/9;
PUT('77°F = ' || C || '°C');

Converts Celsius to Fahrenheit and Fahrenheit to Celsius.

PROGRAM ShoppingCart;
CHARACTER CART(10,20);
INTEGER PRICES(10);
INTEGER COUNT := 0;

PROCEDURE ADDITEM(ITEM,PRICE);
BEGIN
    CART(COUNT) := ITEM;
    PRICES(COUNT) := PRICE;
    COUNT := COUNT + 1;
END ADDITEM;

PROCEDURE REMOVEITEM(IDX);
INTEGER I;
BEGIN
    FOR I := IDX TO COUNT-2 DO
        CART(I) := CART(I+1);
        PRICES(I) := PRICES(I+1);
    END;
    COUNT := COUNT - 1;
END REMOVEITEM;

BEGIN
    CALL ADDITEM('Apple',2);
    CALL ADDITEM('Banana',3);
    CALL REMOVEITEM(0);
END;

Adds and removes items in a shopping cart with total cost.

PROGRAM Greeting;
PROCEDURE GREET(NAME);
BEGIN
    PUT('Hello, ' || NAME || '! Welcome!');
END GREET;

BEGIN
    CALL GREET('Saurav');
    CALL GREET('Alice');
    CALL GREET('Bob');
END Greeting;

Greets users by name.

PROGRAM Stopwatch;
INTEGER TIME := 0;
WHILE TIME < 5 DO
BEGIN
    PUT('Stopwatch: ' || TIME || ' seconds');
    TIME := TIME + 1;
END;
PUT('Done!');

Simulates a stopwatch incrementing seconds.