Moved exercises to exercises because exercises

exercises/12_while2.zig

@@ -0,0 +1,35 @@
+//
+// Zig 'while' statements can have an optional 'continue expression'
+// which runs every time the while loop continues (either at the
+// end of the loop or when an explicit 'continue' is invoked (we'll
+// try those out next):
+//
+//     while (condition) : (continue expression)
+//         ...
+//     }
+//
+// Example:
+//
+//     var foo = 2;
+//     while (foo<10) : (foo+=2)
+//         // Do something with even numbers less than 10...
+//     }
+//
+// See if you can re-write the last exercise using a continue
+// expression:
+//
+const std = @import("std");
+
+pub fn main() void {
+    var n: u32 = 2;
+
+    // Please set the continue expression so that we get the desired
+    // results in the print statement below.
+    while (n < 1000) : ??? {
+        // Print the current number
+        std.debug.print("{} ", .{n});
+    }
+
+    // As in the last exercise, we want this to result in "n=1024"
+    std.debug.print("n={}\n", .{n});
+}