ex1.cpp

#include <iostream>
#include <vector>

using namespace std;

void print_vec(const vector<int> &);

int main() {
  vector<int> test;
  test.push_back(3);
  test.push_back(1);
  test.push_back(4);
  test.push_back(1);
  test.push_back(5);
  test.push_back(9);

  print_vec(test);

  return 0;
}

void print_vec(const vector<int> & v) {
  for (unsigned i = 0; i < v.size(); ++i)
    cout << v.at(i) << endl;
}

ex2.cpp

#include <iostream>
#include <vector>

using namespace std;

void print_vec_rev(const vector<int> &);

int main() {
  vector<int> test;
  test.push_back(3);
  test.push_back(1);
  test.push_back(4);
  test.push_back(1);
  test.push_back(5);
  test.push_back(9);

  print_vec_rev(test);

  return 0;
}

void print_vec_rev(const vector<int> & v) {
  for (int i = v.size() - 1; i >= 0; --i)
    cout << v.at(i) << endl;
}

ex3.cpp

#include <iostream>
#include <vector>

using namespace std;

int main() {
  vector<int> frequencies(100, 0);
  int next = 0;
  while (cin >> next) {
    frequencies.at(next - 1)++;
  }

  int max_freq = 0;
  int max_num = 0;
  for (unsigned i = 0; i < frequencies.size(); ++i) {
    if (frequencies.at(i) > max_freq) {
      max_freq = frequencies.at(i);
      max_num = i + 1;
    }
  }

  cout << "Most frequently occurring number: " << max_num << endl;

  return 0;
}

ex4.cpp

#include <iostream>
#include <vector>

using namespace std;

void print_vec(const vector<string> &);
vector<string> merge(const vector<string> &, const vector<string> &);

int main() {
  vector<string> v1;
  v1.push_back("apple");
  v1.push_back("carrot");
  v1.push_back("disc");

  vector<string> v2;
  v2.push_back("bear");
  v2.push_back("echo");
  v2.push_back("ferret");
  v2.push_back("hamster");

  vector<string> merged = merge(v1, v2);
  print_vec(merged);
}

void print_vec(const vector<string> & v) {
  for (unsigned i = 0; i < v.size(); ++i) 
    cout << v.at(i) << endl;
}

vector<string> merge(const vector<string> & v1, const vector<string> & v2) {
  vector<string> result;
  unsigned i = 0;
  unsigned j = 0;
  while (i < v1.size() && j < v2.size()) {
    if (v1.at(i) < v2.at(j)) {
      result.push_back(v1.at(i));
      ++i;
    } else {
      result.push_back(v2.at(j));
      ++j;
    }
  }

  for (; i < v1.size(); ++i)
    result.push_back(v1.at(i));
  for (; j < v2.size(); ++j)
    result.push_back(v2.at(j));

  return result;
}

ex5.cpp

#include <iostream>

using namespace std;

struct Country {
  string name;
  unsigned population;
  double area;
};

int main() {
  return 0;
}

ex6.cpp

#include <iostream>
#include <vector>

using namespace std;

struct Country {
  string name;
  unsigned population;
  double area;
};

string largest_population(const vector<Country> &);
string largest_area(const vector<Country> &);

int main() {
  Country usa;
  usa.name = "United States of America";
  usa.population = 311000000;
  usa.area = 3794000;

  Country canada;
  canada.name = "Canada";
  canada.population = 34000000;
  canada.area = 3850000;

  Country mexico;
  mexico.name = "Mexico";
  mexico.population = 112000000;
  mexico.area = 1958000;

  vector<Country> countries;
  countries.push_back(usa);
  countries.push_back(canada);
  countries.push_back(mexico);

  cout << "Largest population: " << largest_population(countries) << endl;
  cout << "Largest area: " << largest_area(countries) << endl;

  return 0;
}

string largest_population(const vector<Country> & c) {
  string name = "";
  unsigned largest = 0;
  for (unsigned i = 0; i < c.size(); ++i) {
    if (c.at(i).population > largest) {
      largest = c.at(i).population;
      name = c.at(i).name;
    }
  }

  return name;
}

string largest_area(const vector<Country> & c) {
  string name = "";
  double largest = 0;
  for (unsigned i = 0; i < c.size(); ++i) {
    if (c.at(i).area > largest) {
      largest = c.at(i).area;
      name = c.at(i).name;
    }
  }

  return name;
}