feat: implement sort and binary search to reseach a value in a vector

Author: LeottaAlberto

exercises/verify.cpp

@@ -7,12 +7,71 @@ The number 3 is [not] present in the array.
 */
 
 #include <iostream>
+#include <algorithm>
+#include <vector>
 using namespace std;
 
-int main()
-{
-  // placeholder
-  int N[10] = {3, 4, 5, 1, 2, 3, 4, 9, 13, 0};
+const int ZERO = 48;
+const int NINE = 57;
+const int MAX_DIGIT = 10;
+const int MINUS = 45;
+
+const std::string ERROR_COLOR = "\033[31m";
+const std::string NORMAL_COLOR = "\033[0m";
+
+double insertNumber(const std::string& msg);
+bool checkStringIsNumber(std::string in);
+template <typename T>
+int binarySearch(T item, vector<int>&collection);
+
+int main(){
+  vector<int> collection = {3, 4, 5, 1, 2, 3, 4, 9, 13, 0};
+  sort(collection.begin(), collection.end());
+
+  auto n = insertNumber("Insert number: ");
+
+  int pos;
+  if(pos = binarySearch(n, collection) == -1) cout << "Value Not Found";
+  else cout << "Value found at " << pos << " position";
 
   return 0;
 }
+
+template <typename T>
+int binarySearch(T item, vector<int>&collection) {
+  int start = 0;
+  int end = collection.size()-1;
+  int center;
+  do {
+    center = (start + end) / 2;
+    if(collection[center] == item) return center;
+    if(item > collection[center]) start = center+1;
+    else end = center-1;  
+  } while(start <= end);
+  return -1;
+}
+
+
+double insertNumber(const std::string& msg){
+  std::string insert;
+  bool isCorrect = true;
+  do {
+    if(!isCorrect) std::cout << ERROR_COLOR << "[Insert a valid input] " << NORMAL_COLOR;
+    std::cout << msg;
+    getline(std::cin, insert);
+  } while(!(isCorrect = checkStringIsNumber(insert)));
+
+  return std::stod(insert);
+}
+
+bool checkStringIsNumber(std::string in){
+  if(in.empty()) return false;
+  if(in.size() > MAX_DIGIT) return false;
+  for (std::size_t i = 0; i < in.size(); ++i){
+    if ((in[i] < ZERO || in[i] > NINE)){
+      if (i == 0 && in[i] == MINUS) continue;
+      return false;
+    }
+  }
+  return true;
+}