September 2017 Update

Task/Constrained-random-points-on-a-circle/BBC-BASIC/constrained-random-points-on-a-circle.bbc

@@ -1,8 +0,0 @@
-      MODE 8
-      ORIGIN 640, 512
-      FOR i% = 1 TO 1000
-        x% = RND(31)-16
-        y% = RND(31)-16
-        r = SQR(x%^2 + y%^2)
-        IF r >= 10 IF r <= 15 PLOT x%*2, y%*2
-      NEXT

Task/Constrained-random-points-on-a-circle/Gnuplot/constrained-random-points-on-a-circle.gnuplot

@@ -0,0 +1,27 @@
+## Ring of random points 2/18/17 aev
+reset
+fn="RingRandPntsGnu";
+ttl="Ring of random points"
+ofn=fn.".png"; lim=1000;
+randgp(top) = floor(rand(0)*top)
+set terminal png font arial 12 size 640,640
+set output ofn
+set title ttl font "Arial:Bold,12"
+unset key;
+set size square
+set parametric
+set xrange [-20:20]; set yrange [-20:20];
+set style line 1 lt rgb "red"
+$rring << EOD
+EOD
+set print $rring append
+do for [i=1:lim] {
+  x=randgp(30); y=randgp(30);
+  r=sqrt(x**2+y**2);
+  if (r>=10&&r<=15) \
+    {print x," ",y; print -x," ",-y;print x," ",-y; print -x," ",y;}
+}
+plot [0:2*pi] sin(t)*10,cos(t)*10, sin(t)*15,cos(t)*15 ls 1,\
+$rring using 1:2 with points  pt 7 ps 0.5 lc "black"
+set output
+unset print

Task/Constrained-random-points-on-a-circle/Kotlin/constrained-random-points-on-a-circle.kotlin

@@ -0,0 +1,17 @@
+// version 1.1.3
+
+fun main(args: Array<String>) {
+    val r = java.util.Random()
+    val points = Array(31) { CharArray(31) { ' ' } }
+    var count = 0
+    while (count < 100) {
+        val x = r.nextInt(31) - 15
+        val y = r.nextInt(31) - 15
+        val h = x * x + y * y
+        if (h in 100..225) {
+            points[x + 15][y + 15] = 'o'
+            count++
+        }
+    }
+    for (i in 0..30) println(points[i].joinToString(""))
+}

Task/Constrained-random-points-on-a-circle/Zkl/constrained-random-points-on-a-circle.zkl

@@ -0,0 +1,10 @@
+xy:=(0).walker(*).tweak(fcn{  // generate infinite random pairs (lazy)
+   x:=(-15).random(16); y:=(-15).random(16);
+   if(not (100<=(x*x + y*y)<=225)) Void.Skip else T(x,y)
+});
+
+const N=31;  // [-15..15] includes 0
+array:=(" ,"*N*N).split(",").copy();  // bunch of spaces (list)
+
+xy.walk(100).apply2(fcn([(x,y)],array){array[x+15 + N*(y+15)]="*"},array);
+foreach n in ([0..30]){ array[n*N,30].concat().println(); }