diff -r 448a7a78aa86 -r fca7f33a426c progs/while-tests/collatz2.while
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/progs/while-tests/collatz2.while	Mon Aug 31 16:57:15 2020 +0100
@@ -0,0 +1,27 @@
+// Collatz series
+//
+// needs writing of strings and numbers; comments
+
+bnd := 1;
+while bnd < 101 do {
+  write bnd;
+  write ": ";
+  n := bnd;
+  cnt := 0;
+
+  while n > 1 do {
+    write n;
+    write ",";
+    
+    if n % 2 == 0 
+    then n := n / 2 
+    else n := 3 * n+1;
+
+    cnt := cnt + 1;
+  };
+
+  write " => ";
+  write cnt;
+  write "\n";
+  bnd := bnd + 1;
+};  
\ No newline at end of file