state_sort.cpp

#include <iostream>
#include <algorithm>

struct state {
  std::string name;
  float unemployed_2007;
  float unemployed_2015;
};

bool cmp_unemploy_asc(struct state lhs, struct state rhs) {
  return (lhs.unemployed_2015 - lhs.unemployed_2007) <
    (rhs.unemployed_2015 - rhs.unemployed_2007);
}

bool cmp_unemploy_desc(struct state lhs, struct state rhs) {
  return (lhs.unemployed_2015 - lhs.unemployed_2007) >
    (rhs.unemployed_2015 - rhs.unemployed_2007);
}

int main(int argc, char** argv) {

  struct state* states = new struct state[3];
  states[0].name = "Oregon";
  states[0].unemployed_2007 = 5.2;
  states[0].unemployed_2015 = 5.7;
  states[1].name = "California";
  states[1].unemployed_2007 = 5.4;
  states[1].unemployed_2015 = 6.2;
  states[2].name = "Pennsylvania";
  states[2].unemployed_2007 = 4.4;
  states[2].unemployed_2015 = 5.1;

  std::cout << "Before sort:" << std::endl;
  for (int i = 0; i < 3; i++) {
    std::cout << "  " << states[i].name << "\t"
      << states[i].unemployed_2015 - states[i].unemployed_2007 << std::endl;
  }

  std::sort(states, states + 3, cmp_unemploy_desc);
  std::cout << "After descending sort:" << std::endl;
  for (int i = 0; i < 3; i++) {
    std::cout << "  " << states[i].name << "\t"
      << states[i].unemployed_2015 - states[i].unemployed_2007 << std::endl;
  }

  std::sort(states, states + 3, cmp_unemploy_asc);
  std::cout << "After ascending sort:" << std::endl;
  for (int i = 0; i < 3; i++) {
    std::cout << "  " << states[i].name << "\t"
      << states[i].unemployed_2015 - states[i].unemployed_2007 << std::endl;
  }
}