BASIC - Programming Language

BASIC: THE  FEELING  OF  THE  GOOD  OLD  TIMES !
                  10  INPUT  A
                  20  B = SIN(A)
                  30  PRINT  "ANSWER: ", B
                  40  END                       

BASIC  USER'S  GUIDE:

•  PRINT

     10  PRINT "HELLO  WORLD !"
     20  END


•  INPUT

     10  INPUT  “A=”, A
     20  PRINT  A
     30  END


•  IF...THEN...

     Number Comparison:

     10  INPUT  A
     20  IF  A＞90  THEN  B=“A”
     30  PRINT  B
     40  END

    Conditional Operators:
    ＞          greater than
    ＜          less than
    ＞=        greater than or equal to 
     =＞       equal to or greater than 
    ＜=        less than or equal to
     =＜       equal to or less than
     =           equal to
     ==         equal to
    ＜＞       not equal to
    !=           not equal to

     THEN can be followed by  GOTO, GOSUB, INPUT, PRINT.

    String Comparison:

     10  INPUT A
     20  IF A=“TOM” THEN PRINT “BOY”
     30  END

    Conditional Operators:

     =          is
     ==        is 
    ＜＞       is not
     !=          is not


•  FOR...NEXT...

     10  FOR  I=1  TO  4  STEP  2
     20  PRINT  “HELLO”, I
     30  NEXT  I
     40 END

     STEP specifies the counter increment for each loop. If STEP doesn’t exit, the default increment is 1.

     FOR...NEXT... loop can be nested.

     10  FOR  I=1  TO  5
     20  FOR  J=1  TO  4
     30  PRINT  I, J
     40  NEXT  J
     50  NEXT  I
     60 END


•  GOTO

     10  ...
     20  ...
     30  ...
     40  GOTO  10
     50  ...


•  GOSUB

     10  PRINT  “H”
     20  GOSUB  100
     30  PRINT  “L”
     40  END
     100  PRINT  “A”
     110 RETURN


•  SOUND

     10  SOUND  C, M, 0.5

     The line 10 plays Middle C piano note for 0.5 seconds.

     Note: C, C#, D, D#, E, F, F#, G, G#, A, A#, B
     Pitch Range: L (low), M (middle), H (high)
     Lasting Time: specifies how long a note lasts.

     C, D, E, F, G, A, B can also be labeled as 1, 2, 3, 4, 5, 6, 7. (C# as 1#). 


•  TEXT

     10  TEXT  “HELLO”, x, y, size

    (x,y):  position of the string “HELLO”.


•  CIRCLE

     10  CIRCLE  x,  y,  radius

     (x,y): the center of the circle.


•  RECTANGLE

     10  RECT  x,  y,  width,  height 

     (x,y): top-left point of the rectangle.


•  LINE

     10  LINE  x1,  y1,  x2,  y2 

    (x1,y1): the starting point of the line.
    (x2,y2): the ending  point of the line.


•  POINT

     10  POINT  x, y

    (x,y): the position of the point.


•  CLR:  clear the edit window.
•  CLS:  clear the graph window.


•  DELAY

     10  DELAY  0.5

     0.5:lasting time in seconds

     This function is used to suspend execution of a program for a particular time.


•  CURVE

     10  CURVE  x,  y,  radius,  0,  PI 

     0: starting angle
     PI: ending angle

     The curve draws clockwise with center (x,y). 


•  Mathematical Functions:

     SIN(X), COS(X), TAN(X), COT(X),
     ASIN(X), ACOS(X), ATAN(X),
     SINH(X), COSH(X), TANH(X),
     ASINH(X), ACOSH(X), ATANH(X).

     SQR(X): square root of x.
     ABS(X): absolute value of x.
     FCT(X): x factorial.
     LOG(X): natural logarithm of x.
     LOG10(X): base-10 logarithm of x.
     LOG2(X) :base-2 logarithm of x.
     EXP(X): base-e exponential of x.
     ERF(X): the error function of x.
     ERFC(X): the complementary error function of x.
     ROUND(X) :integral nearest to x.
     CEIL(X): the smallest integral that is not less than x.
     FLOOR(X): the largest integral that is not greater than x.
     TGAMMA(X): the gamma function of x.
     LGAMMA(X): the natural logarithm of the absolute value of the gamma function of x.


•  Reserved Variables:

     INKEY :  once a key is pressed, the value of INKEY changes.
     RND    :  a random number.
     PI        :  π


•  Some Tips:

     1. Undo & Redo typing on iPhone with a shake.
     2. Copy an Emoji or some character from other places (like Notes), then paste them on the edit window.
     3. Exponentiation is expressed as X^Y.