72 lines
2.7 KiB
C++
72 lines
2.7 KiB
C++
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// fig14_17.cpp
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// Demonstrating projections with C++20 range algorithms.
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#include <array>
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#include <algorithm>
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#include <fmt/format.h>
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#include <iostream>
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#include <iterator>
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#include <string>
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#include <string_view>
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class Employee {
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public:
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Employee(std::string_view first, std::string_view last, int salary)
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: m_first{first}, m_last{last}, m_salary{salary} {}
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std::string getFirst() const {return m_first;}
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std::string getLast() const {return m_last;}
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int getSalary() const {return m_salary;}
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private:
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std::string m_first;
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std::string m_last;
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int m_salary;
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};
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// operator<< for an Employee
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std::ostream& operator<<(std::ostream& out, const Employee& e) {
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out << fmt::format("{:10}{:10}{}",
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e.getLast(), e.getFirst(), e.getSalary());
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return out;
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}
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int main() {
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std::array employees{
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Employee{"Jason", "Red", 5000},
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Employee{"Ashley", "Green", 7600},
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Employee{"Matthew", "Indigo", 3587}
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};
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std::ostream_iterator<Employee> output{std::cout, "\n"};
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std::cout << "Employees:\n";
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std::ranges::copy(employees, output);
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// sort Employees by salary; {} indicates that the algorithm should
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// use its default comparison function
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std::ranges::sort(employees, {},
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[](const auto& e) {return e.getSalary(); });
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std::cout << "\nEmployees sorted in ascending order by salary:\n";
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std::ranges::copy(employees, output);
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// sort Employees by salary in descending order
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std::ranges::sort(employees, std::ranges::greater{},
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&Employee::getSalary);
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std::cout << "\nEmployees sorted in descending order by salary:\n";
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std::ranges::copy(employees, output);
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}
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/**************************************************************************
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* (C) Copyright 1992-2021 by Deitel & Associates, Inc. and *
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* Pearson Education, Inc. All Rights Reserved. *
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* *
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* DISCLAIMER: The authors and publisher of this book have used their *
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* best efforts in preparing the book. These efforts include the *
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* development, research, and testing of the theories and programs *
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* to determine their effectiveness. The authors and publisher make *
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* no warranty of any kind, expressed or implied, with regard to these *
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* programs or to the documentation contained in these books. The authors *
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* and publisher shall not be liable in any event for incidental or *
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* consequential damages in connection with, or arising out of, the *
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* furnishing, performance, or use of these programs. *
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**************************************************************************/
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