Basics of Cpp vector

Author: priteshgohil

008_Vector_and_Function.cpp

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+#include <iostream>
+#include <vector>
+// #include <numeric> //std::iota
+
+// Compared to Arrays, Vectors are not memory efficient and time consuming to
+// access vector elements
+
+void Reverse(const std::vector<int>&);
+void PrintVectorVert (const std::vector<int>&); //Always pass by reference,
+//cz saves a lot of memory. also you always dont need a copy of vector
+
+int main(int argc, char const *argv[]) {
+
+  // Initialize
+  std::vector<int> nVect1;          // Empty vector
+  std::vector<int> nVect2 (100, 1);  // A vector containing 100 items: All 1s.
+  std::vector<int> nVect3 {100, 1};  // A vector containing 2 items: 100 and 1.
+  std::vector<int> nVect4 (nVect3.begin(), nVect3.end()); //iterate nVect3 & fill
+  std::vector<int> nVect5 (nVect4);  // Copy nVect4
+
+  // Vector from ArraySum
+  double dArr1[] = {1.0, 2.0, 3.0, 4.0};
+  std::vector<double> dVect6 (dArr1, dArr1 + sizeof(dArr1)/sizeof(*dArr1));
+
+  PrintVectorVert(nVect3);
+  nVect3.push_back(11); //insert at the end of vector
+  nVect3.push_back(22);
+  nVect3.insert(nVect3.begin(), 999); //insert element before specified index
+  nVect3.insert(nVect3.begin()+3, 555);
+  std::cout << nVect3.at(2) << '\n';  //vector value at given index
+  std::cout << nVect3.size() << '\n'; //vector size
+  PrintVectorVert(nVect3);
+
+  //Erase vector
+  nVect3.erase(nVect3.begin()+2); //remove element at given index
+  std::cout << "\nRemove 3rd vector element" << '\n';
+  PrintVectorVert(nVect3);
+  Reverse(nVect3);
+
+  // Clear vector
+  // nVect3.erase(nVect3.begin(), nVect3.end()); //Erase everything
+  nVect3.clear();
+  std::cout << "\nClear all vector element" << '\n';
+  std::cout << "Empty? " << nVect3.empty() << '\n';
+
+
+  // std::vector<int> nX(10);
+  // std::iota(std::begin(nX), std::end(nX), 0);//range of 0 to 9; 0 starting num
+
+  return EXIT_SUCCESS;
+}
+
+
+void PrintVectorVert (const std::vector<int>& nVect){
+  std::cout << "\n";
+  for(unsigned int i = 0; i < nVect.size(); i++) {
+    std::cout << "v[" << i << "] = " << nVect[i] << '\n';
+  }
+}
+
+void Reverse(const std::vector<int>& nVect){
+  std::cout << "\nReveresed vector" << std::endl;
+  for (size_t i = nVect.size(); i >0; i--) { //size_t: unsigned integer
+    std::cout << "v[" << i-1 << "] = " << nVect[i-1] << '\n';
+  }
+}