diff --git a/programming/exercises/control_structures.m b/programming/exercises/control_structures.m
index 4608281..f480ef5 100644
--- a/programming/exercises/control_structures.m
+++ b/programming/exercises/control_structures.m
@@ -188,3 +188,38 @@ disp(x)
 
 %% 8 Teste den Zufallsgenerator
 
+x           = rand(1000,1); % some random numbers
+count       = zeros(5,1);
+for i=1:length(x)
+    if(x(i) < 0.2)
+        count(1) = count(1) + 1;
+    elseif(x(i) < 0.4)
+        count(2) = count(2) + 1;
+    elseif(x(i) < 0.6)
+        count(3) = count(3) + 1;
+    elseif(x(i) < 0.8)
+        count(4) = count(4) + 1;
+    else
+        count(5) = count(5) + 1;
+    end
+end
+disp(count)
+% Die Erwartung waere eine Gleichverteilung.
+
+%% 9) String parsing
+
+filename = '2015-10-12_100Hz_1.25V.dat';
+
+% a
+positions = [1];
+for i = 1:length(filename)
+    if filename(i) == '_'
+        positions = cat(1, positions, i);
+    end
+end
+positions = cat(1, positions, length(filename))
+disp(positions)
+
+for i = 2:length(positions)
+    disp(char(filename(positions(i-1):positions(i))))
+end
\ No newline at end of file