add missing ex from mwp paper

Author: nkrusch

c_files/original_paper/example3_5.c

@@ -0,0 +1,8 @@
+/*
+ * Example 3.5 from the original paper "A Flow Calculus of
+ * mwp-Bounds for Complexity Analysis".
+ */
+int foo(int X1, int X2){
+    for(int i=0; i<X3; i++)
+        X1 = X1 + X2;
+}

c_files/readme.md

@@ -39,6 +39,7 @@
 |                          | `example3_2.c`        | Three variables and `while` loop                             |
 |                          | `example3_4.c`        | Iteration with 5 variables, using while (W) rule             |
 |                          | `example3_4_loop.c`   | Iteration with 5 variables, using loop (L) rule              |
+|                          | `example3_5.c`        | Iteration with 3 variables, where some derivation paths fail |
 |                          | `example5_1.c`        | Adding two variables                                         |
 |                          | `example7_10.c`       | program with `if...else` and 3 variables                     |
 |                          | `example7_11.c`       | Binary operations with 4 variables                           |