fixed binary_search for lgtm errors + added tests

searching/binary_search.c

@@ -1,9 +1,21 @@
+/**
+ * @file
+ * @brief Program to perform [binary
+ * search](https://en.wikipedia.org/wiki/Binary_search_algorithm) of a target
+ * value in a given *sorted* array.
+ */
+#include <assert.h>
 #include <stdio.h>
 
-// Recursive Function- It returns location of x assumiung array arr[l..r] is
-// present, otherwise -1
-
-int binarysearch(int arr[], int l, int r, int x)
+/** Recursive implementation
+ * \param[in] arr array to search
+ * \param l left index of search range
+ * \param r right index of search range
+ * \param x target value to search for
+ * \returns location of x assuming array arr[l..r] is present
+ * \returns -1 otherwise
+ */
+int binarysearch(const int *arr, int l, int r, int x)
 {
     if (r >= l)
     {
@@ -25,18 +37,33 @@ int binarysearch(int arr[], int l, int r, int x)
     return -1;
 }
 
-int main(void)
+/** Test implementations */
+void test()
 {
     // give function an array to work with
     int arr[] = {2, 3, 4, 10, 40};
     // get size of array
     int n = sizeof(arr) / sizeof(arr[0]);
+
+    printf("Test 1.... ");
     // set value to look for
     int x = 10;
     // set result to what is returned from binarysearch
     int result = binarysearch(arr, 0, n - 1, x);
-    // print out result
-    (result == -1) ? printf("Element is not in the array\n")
-                   : printf("Element is present at index %d\n", result);
+    assert(result == 3);
+    printf("passed\n");
+
+    printf("Test 2.... ");
+    x = 5;
+    // set result to what is returned from binarysearch
+    result = binarysearch(arr, 0, n - 1, x);
+    assert(result == -1);
+    printf("passed\n");
+}
+
+/** Main function */
+int main(void)
+{
+    test();
     return 0;
 }