clean up of bsearch

1 files changed, 38 insertions, 24 deletions

diff --git a/impls/bsearch.cpp b/impls/bsearch.cpp
index 6172b15..cc7b8e8 100644
--- a/impls/bsearch.cpp
+++ b/impls/bsearch.cpp
@@ -4,6 +4,7 @@
  */
 
 #include <algorithm>
+#include <cassert>
 #include <cstdlib>
 #include <fstream>
 #include <iostream>
@@ -17,9 +18,7 @@ using std::ostream;
 using std::string;
 using std::vector;
 
-vector<int> arr;
-
-ostream &print_arr(ostream &os)
+ostream &print_arr(ostream &os, std::vector<int> &arr)
 {
   os << "[";
   for (size_t i = 0; i < arr.size(); ++i)
@@ -27,31 +26,46 @@ ostream &print_arr(ostream &os)
   return os << "]";
 }
 
-int bsearch(int n, int l = 0, int u = arr.size() - 1)
+int bsearch(int n, std::vector<int> arr)
 {
-  int midpoint = ((u + l) / 2);
-  if (l >= u || u <= 0)
-    return -1;
-  int val = arr[midpoint];
-  if (val == n)
-    return midpoint;
-  else if (val > n)
-    return bsearch(n, l, midpoint - 1);
-  else
-    return bsearch(n, midpoint + 1, u);
+  int l = 0;
+  int u = arr.size() - 1;
+  while (l <= u)
+  {
+    int midpoint = l + ((u - l) / 2);
+    int val      = arr[midpoint];
+
+    if (val == n)
+    {
+      return midpoint;
+    }
+    else if (val > n)
+    {
+      u = midpoint - 1;
+    }
+    else
+    {
+      l = midpoint + 1;
+    }
+  }
+  return -1;
 }
 
-int main(void)
+int main(int argc, char *argv[])
 {
-  std::ifstream input("bsearch.txt");
-  string line;
-  while (std::getline(input, line))
-    arr.push_back(std::stoi(line));
+  std::ifstream input(argc > 1 ? argv[1] : "bsearch.txt");
+  std::vector<int> arr;
+
+  for (std::string line; std::getline(input, line);
+       arr.push_back(std::stoi(line)))
+    continue;
+
   std::sort(std::begin(arr), std::end(arr));
-  string inp;
-  cout << "Enter number to search: ";
-  cin >> inp;
-  int to_search = std::stoi(inp);
-  cout << bsearch(to_search) << endl;
+
+  for (size_t i = 0; i < arr.size(); ++i)
+  {
+    int index = bsearch(arr[i], arr);
+    assert(index == (int)i);
+  }
   return 0;
 }