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.