Renamed top-level folders to use underscores instead of dashes.

arrays_strings/reverse_string/reverse_string.cpp

@@ -0,0 +1,36 @@
+#include <stdio.h>
+
+void Reverse(char* str) {
+    if (str) {
+        char* i = str;	// first letter
+        char* j = str;	// last letter
+
+        // find the end of the string
+        while (*j) {
+            j++;
+        }
+
+        // don't point to the null terminator
+        j--;
+
+        char tmp;
+
+        // swap chars to reverse the string
+        while (i < j) {
+            tmp = *i;
+            *i++ = *j;
+            *j-- = tmp;
+        }
+    }
+}
+
+int main() {
+    char test0[] = "";
+    char test1[] = "foo";
+    Reverse(NULL);
+    Reverse(test0);
+    Reverse(test1);
+    printf("%s \n", test0);
+    printf("%s \n", test1);
+    return 0;
+}