如何使数组显示升序和降序

Question

我是stackoverflow的新手，有人给我一个评估要完成，但我似乎无法让它按我想要的方式工作。我的第一部分工作得很好，但数组的第二部分不工作，而且我希望它按升序和降序显示数组。任何帮助都将是伟大的感谢

// Test4.cpp : This file contains the 'main' function. Program execution begins and ends there.
//
/* For this assessment I am required to create a menu system consisting of 3 options 1 to generate a username, 2 to sort an array in ascending and descending order and 3 to exit.

The menu should be displayed as shown

1. String Functions
2. Array Functions
3. Exit
*/
#include <iostream>
#include <string>
#include <algorithm>
#include <conio.h>
using namespace std;
// Here are the methods I will use
void display_menu();
void create_name();
void menu_act_on_choice(int choice_in);
void generate_and_display_name(string name_in);
//global double array
double calcTimes[] = { 21.23,23.45,23.71,22.22,24.12,21.23,21.23,21.45 };
void display_menu()
{
/*
do
display menu options
prompt for and read value for choice
if choice <> 4 (quit option)
call menu_act_on_choice passing value of choice
while choice is not equal to 4 (quit option)
*/
// local variables
int choice = 0;
do
{
system("cls");
cout << "Make your selection from the following options" << endl
<< "1. String Functions" << endl
<< "2. Array Functions" << endl
<< "3. Exit" << endl;
cout << "> ";
cin >> choice;
menu_act_on_choice(choice);
} // end do
while (choice != 4);
} // end method
void menu_act_on_choice(int choice_in)
{
switch (choice_in)
{
case 1:
create_name();
break;
case 2:
void array_length();
break;
case 3:
break;
}// end switch
}
void create_name()
{
/*
prompt for first name and second name
using getline read in name in format first name and last name
ignore white space
call create_name() passing name as parameter
*/
// local variables
string name = "";

cout << "Enter your full name: ";
cin.ignore();
getline(cin, name);
generate_and_display_name(name);
} // end method
void generate_and_display_name(string name_in)
{
// local variables
string string1;
int position = 0;
string string2;
// add first character to string 1
string1.assign(name_in, 0, 1);
// find position of space
position = name_in.find(" "); // position of first space
// assign lastname to string 2, position +1 to end of string
string2.assign(name_in, position + 1, name_in.length());
//concatenate both strings
string1.append(string2);
// Print name
cout << "Your username is " << string1 << endl;
cout << "Press any key to return to the menu ";
cin.ignore();
} // end method
void array_length()
{
// stage 1 find the total size of the array in bytes
int stage1 = sizeof(calcTimes);
cout << "The array is " << stage1 << " bytes" << endl;

// stage 2 find the size of a single element
int stage2 = sizeof(calcTimes[0]);  // or sizeof(int)
cout << "A single element is " << stage2 << " bytes" << endl;

// stage 3 calculate how many elements stage 1 / stage 2

int stage3 = (stage1 / stage2);
cout << "There are " << stage3 << " elements" << endl;
}

int main()
{
display_menu();
}

Answer 1

我建议使用std::sort:

示例：

#include <array>       // std::begin, std::end
#include <algorithm>   // std::sort
#include <functional>  // std::less, std::greater
#include <iostream>
int main() {
double calcTimes[] = { 21.23,23.45,23.71,22.22,24.12,21.23,21.23,21.45 };

// ascending order (std::less<>{} is the default and can be left out)
std::sort(std::begin(calcTimes), std::end(calcTimes), std::less<>{});
// print the result
for(double value : calcTimes) std::cout << value << 'n';

// decending order
std::sort(std::begin(calcTimes), std::end(calcTimes), std::greater<>{});
// print the result
for(double value : calcTimes) std::cout << value << 'n';
}