Added c files for TP frama-c

TP5/Exo6/exo6.h

+#include "limits.h"
+
+/**
+ * @brief Computes the min of these arguments.
+ * 
+ * @param a an integer
+ * @param b an integer
+ * @param c an integer
+ * @return int The smallest value among a, b and c.
+ */
+int min(int a, int b, int c);
+
+/**
+ * @brief Computes the next step of @p a in the Syracuse sequence, i.e., its quotient by 2 if @p a is even, and 3 * @p a +1 otherwise.
+ * 
+ * @param a an integer.
+ * @return int The next value in the Syracuse sequence.
+ */
+int syracuseStep(int a);
+
+/**
+ * @brief Computes the rounding of the (real) quotient of a by b, i.e. the closest integer to the quotient. We will accept a function that does that only for positive integers (remember the C int division is not the Euclidean division). As a bonus, you might implement a function that works for any pair of integer (such that the quotient is defined of course).
+ *
+ * @param a the dividend
+ * @param b the diviser
+ * @return int The rounding of a/.b.
+ * @pre a and b are positive (or not, depending of your implementation).
+ * @pre b is not 0.
+ */
+int roundedDiv(int a, int b);
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