Generate random quadratic equations and plot them

[Richard Frost]

Polished up ancient CGA code because I saw the word "quadratic" on
Discord, and don't feel like doing real work!

Code: QB64: [Select]

1. DEFINT A-Z
2.  
3. DECLARE FUNCTION Eq! (x!)
4. DECLARE SUB Wubba ()
5.  
6. COMMON SHARED minx!, miny!, ma, xx!, maxy!, r1!, r2!, vx!, vy!, sx!, sy!, s!
7.  
8. DIM SHARED a, b, c
9. DIM SHARED c(4), c$(4), r$(30), white
10.  
11. white = _RGB32(222, 222, 222)
12.  
13. SCREEN _NEWIMAGE(800, 600, 32)
14. RANDOMIZE TIMER
15.  
16. Begin:
17. WINDOW
18. CLS
19. FOR i = 1 TO 4
20.     c(i) = RND * 9 + 1
21.     IF (RND * 9) > 5 THEN c(i) = -c(i)
22.     'c(1) = -1: c(2) = 1: c(3) = -1: c(4) = 3
23.     c$(i) = LTRIM$(STR$(c(i)))
24.     IF i < 3 THEN
25.         IF c(i) = 1 THEN c$(i) = ""
26.         IF c(i) = -1 THEN c$(i) = "-"
27.     ELSE
28.         IF c(i) > 0 THEN c$(i) = "+" + c$(i)
29.     END IF
30. NEXT i
31. s1$ = "(" + c$(1) + "x" + c$(3) + ")"
32. s2$ = "(" + c$(2) + "x" + c$(4) + ")"
33. s$ = s1$ + " " + s2$
34. x2 = c(1) * c(2)
35. x2$ = LTRIM$(STR$(x2))
36. IF x2$ = "1" THEN x2$ = ""
37. IF x2$ = "-1" THEN x2$ = "-"
38. x1 = c(1) * c(4) + c(2) * c(3): IF x1 = 0 THEN GOTO Begin
39. x1$ = LTRIM$(STR$(x1)): IF x1 > 0 THEN x1$ = "+" + x1$: IF x1 = 1 THEN x1$ = "+"
40. x0 = c(3) * c(4)
41. x0$ = LTRIM$(STR$(x0)): IF x0 > 0 THEN x0$ = "+" + x0$
42. q$ = x2$ + "x" + CHR$(253) + x1$ + "x" + x0$
43. r$(1) = q$
44. r$(2) = s$
45.  
46. a = x2: b = x1: c = x0
47. d1# = b
48. d1# = d1# * b
49. d2# = a
50. d2# = 4 * d2# * c
51. dis! = d1# - d2#
52.  
53. r1! = -777: r2! = -777
54. r$(5) = ""
55. r$(6) = ""
56. IF dis! >= 0 THEN
57.     r$(5) = "bý-4ac" + STR$(dis!)
58.     dis! = SQR(dis!)
59.     r$(6) = "dis=" + STR$(dis!)
60.     r1! = (-b + dis!) / (2 * a)
61.     r2! = (-b - dis!) / (2 * a)
62. END IF
63. IF r1! > r2! THEN SWAP r1!, r2!
64. vx! = (r1! + r2!) / 2
65. vy! = a * vx! * vx! + b * vx! + c
66. r$(3) = "x=" + LTRIM$(STR$(r1!)) + "," + LTRIM$(STR$(r2!))
67. t = ABS(r2! - r1!) + 2 * .5
68. minx! = r1! - t
69. maxx! = r2! + t
70. IF minx! = maxx! THEN
71.     minx! = minx! - 10
72.     maxx! = maxx! + 10
73. END IF
74.  
75. miny! = -10: maxy! = 10
76. FOR pass = 0 TO 1
77.     IF pass = 0 THEN
78.         s! = (maxx! - minx!) / 100
79.     ELSE
80.         Wubba
81.         s! = (maxx! - minx!) / 300
82.     END IF
83.     sx! = (maxx! - minx!) / 180
84.     sy! = (maxy! - miny!) / 20
85.     FOR x! = minx! - s! TO maxx! - s! STEP s!
86.         ty! = Eq!(x!)
87.         IF pass = 1 THEN CIRCLE (x!, ty!), sx! / 10
88.     NEXT x!
89. NEXT pass
90. WINDOW
91.  
92. DO: _LIMIT 10
93.     i$ = INKEY$
94.     IF i$ = CHR$(13) THEN GOTO Begin
95. LOOP UNTIL i$ = CHR$(27)
96. SYSTEM
97.  
98. FUNCTION Eq! (x!)
99.     Eq! = a * x! * x! + b * x! + c
100. END FUNCTION
101.  
102. SUB Wubba
103.     z! = 1.8
104.     minx! = -.5
105.     IF vx! <= minx! THEN minx! = vx!
106.     IF r1! <= minx! THEN minx! = r1!
107.     IF r2! <= minx! THEN minx! = r2!
108.     minx! = minx! * z!
109.  
110.     maxx! = .5
111.     IF vx! >= maxx! THEN maxx! = vx!
112.     IF r1! >= maxx! THEN maxx! = r1!
113.     IF r2! >= maxx! THEN maxx! = r2!
114.     maxx! = maxx! * z!
115.  
116.     IF vy! < 0 THEN
117.         miny! = vy! + vy! * z!
118.         maxy! = vy! * -z!
119.     ELSE
120.         maxy! = vy! + vy! * z!
121.         miny! = vy! * -z!
122.     END IF
123.     IF miny! = 0 THEN miny! = -5
124.     IF maxy! = 0 THEN maxy! = 10
125.  
126.     WINDOW
127.     CLS
128.     WINDOW (minx!, miny!)-(maxx!, maxy!)
129.  
130.     LINE (minx!, 0)-(maxx!, 0) ' x axis
131.     LINE (0, miny!)-(0, maxy!) ' y axis
132.  
133.     s = (maxx! - minx!) / 10
134.     IF s < 1 THEN s = 1
135.     FOR t! = minx! TO maxx! STEP s / 10 ' x axis ticks
136.         tx = PMAP(t!, 0)
137.         ty = PMAP(0, 1)
138.         WINDOW
139.         LINE (tx, ty)-(tx, ty + 1), 1
140.         WINDOW (minx!, miny!)-(maxx!, maxy!)
141.     NEXT t!
142.     FOR t = INT(minx!) TO maxx! STEP s ' x numbers
143.         tx = PMAP(t, 0)
144.         ty = PMAP(0, 1)
145.         WINDOW
146.         LINE (tx, ty)-(tx, ty + 3), 1
147.         IF t <> 0 THEN _PRINTSTRING (tx - 4, ty + 7), LTRIM$(STR$(t))
148.         WINDOW (minx!, miny!)-(maxx!, maxy!)
149.     NEXT t
150.  
151.     s = (maxy! - miny!) / 5
152.     IF s = 0 THEN s = 1
153.     FOR t! = INT(miny!) TO maxy! STEP s / 10 ' y axis ticks
154.         tx = PMAP(0, 0)
155.         ty = PMAP(t!, 1)
156.         WINDOW
157.         LINE (tx, ty)-(tx - 1, ty)
158.         WINDOW (minx!, miny!)-(maxx!, maxy!)
159.     NEXT t!
160.     FOR t = INT(miny!) TO maxy! STEP s ' y axis numbers
161.         tx = PMAP(0, 0)
162.         ty = PMAP(t, 1)
163.         WINDOW
164.         LINE (tx, ty)-(tx - 3, ty)
165.         IF t <> 0 THEN _PRINTSTRING (tx + 6, ty - 6), LTRIM$(STR$(t))
166.         WINDOW (minx!, miny!)-(maxx!, maxy!)
167.     NEXT t
168.  
169.     LINE (vx!, vy!)-(vx!, 0), _RGB32(222, 22, 22) ' vertical vertex to x axis
170.     LINE (vx!, vy!)-(0, vy!), _RGB32(222, 22, 22) ' horizontal to y axis
171.     r$(4) = "v=" + STR$(vx!) + "," + STR$(vy!)
172.  
173.     ml = 0
174.     FOR i = 1 TO 4
175.         p = LEN(r$(i))
176.         IF p > ml THEN ml = p
177.     NEXT i
178.     tx = PMAP(0, 0): ty = PMAP(0, 1)
179.     IF (tx > 400) AND (ty < 300) THEN q = 1
180.     IF (tx < 400) AND (ty < 300) THEN q = 2
181.     IF (tx < 400) AND (ty > 300) THEN q = 3
182.     IF (tx > 400) AND (ty > 300) THEN q = 4
183.     IF q < 3 THEN ty = 500 ELSE ty = 10
184.     IF (q = 1) OR (q = 4) THEN tx = 0 ELSE tx = 800 - ml * 10
185.     WINDOW
186.     FOR r = 1 TO 4
187.         _PRINTSTRING (tx + 10, ty + r * 16), r$(r)
188.     NEXT r
189.     WINDOW (minx!, miny!)-(maxx!, maxy!)
190. END SUB
191.  
192.  

[bplus]

Man I wish I had QB64 when I was in HS. Nice work :)

[STxAxTIC]

Oh damn I missed this!