Question

我正在尝试命令我的程序反转一组随机数组。我让我的程序得到10位数字（范围从60-100），当生成随机数组时，我得到它给我4个选项;例如：

66 75 84 93 82 61 66 99 85 93

R - 反向。（这会将阵列设置反转为[93 85 99 66 ... 84 75 66]）

S - 用于搜索。（这将提示您搜索一个数字并读取它将位于哪一行。）

E - 退出。（退出程序）

A - for add ..（这将添加所有随机数组编号。）

一切都很好，但我遇到的唯一问题是它不会反转随机生成的数组。我以为我提升了正确的命令。我需要帮助，请记住我是C ++的新手。

#include <iostream>
#include <stdlib.h>
#include <time.h>

 using namespace std;

 int main ()
 {
  srand(time(0));
  int arr[10],i,sum;
  bool found;
  char choice;
  for (i = 0; i < 10; i++){
    arr[i] = rand() % 30 + 60;
   }


cout << "The random generated array is: \n";
for (i = 0; i <10; i++){
    cout << arr[i] << "  ";
}

cout << "\n\nR[reverse]\t[S]search\t[E]exit\t\t[A]add\nSelect an option: ";
cin >> choice;
switch (choice){
main ();
    case 'R':
    case 'r':
        cout << "\nThe reversed array is: ";
            for (i = 9; i >=0; i--)
            cout << endl << endl << "------------------------------" << endl;

   main ();
       case 'A':
       case 'a':
        cout << "\nThe sum of the array element is ";
        sum = 0;
            for (i = 0; i < 10; i++) sum += arr[i];
            cout << sum << "\n";
            cout << endl << endl << "----------------------"    << endl;
   main ();
        case 'S':
        case 's':
        cout << "\nPlease insert an element to find: ";
        int find;
        found=false;
        cin >> find;
            for (i = 0; i<10; i++){
                if(arr[i] == find){
                    if(i ==0)
            cout << "\nThe number " << find << " has been found at the 1st position" << endl; 
                else if(i == 1) cout << "\nThe number " << find << " has been found at the 2nd position" << endl;
                else if(i == 2) cout << "\nThe number "  << find << " has been found at the 3rd positon" << endl;
                else if(i == 3) cout << "\nThe number " << find << " has been found at the 4th position" << endl;
                else if(i == 4) cout << "\nThe number " << find << " has been found at the 5th position" << endl;
                else if(i == 5) cout << "\nThe number " << find << " has been found at the 6th position" << endl;
                else if(i == 6) cout << "\nThe number " << find << " has been found at the 7th position" << endl;
                else if(i == 7) cout << "\nThe number "  << find << " has been found at the 8th position" << endl;
                else if(i == 8) cout << "\nThe number " << find << " has been found at the 9th position" << endl;
                else if(i == 9) cout << "\nThe number " << find << " has been found at the 10th position" << endl;
                found = true;
                }
            }
            if(found) cout << "\nElement not found\n";
            cout << endl << endl << "----------------------" << endl;
        main();

        case 'E':
        case 'e':
            break;
}
return 0;
   }

编辑：好的，我刚发布了整个代码，所以你可以看到更好的债务。那是我的意思。抱歉。

Answer 1

使用std::reverse()功能撤消订单：

#include <iostream>
#include <algorithm>

int main(){

    int myArray[10] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
    std::reverse(std::begin(myArray), std::end(myArray));
    for (const auto& arr : myArray) {
        std::cout << arr << std::endl;
    }
    return 0;
}

或制作一个简单的功能：

#include <iostream>

void reverseArray(int a[], int n)
{
    int temp;
    for (int i = 0; i < n / 2; i++)
    {
        temp = a[n - i - 1];
        a[n - i - 1] = a[i];
        a[i] = temp;
    }
}

int main(){

    int myArray[10] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
    reverseArray(myArray, 10);
    for (const auto& arr : myArray) {
        std::cout << arr << std::endl;
    }
    return 0;
}

您应该考虑使用std::vector或其他顺序容器。

Answer 2

你不打印 i 数组arr[i]的元素，你只需要打印破折号。

cout << endl << endl << "------------------------------" << endl;

你也可以区别对待大写和小写：

case 'R':
case 'r':

其中＆＃39; r＆＃39;在您的帮助选项中未提及。

Answer 3

要反转数组，您必须#include <algorithm>。语法如下所示：reverse(arrayName, arrayName + arraySize);

在您的情况下，它应该写成：reverse(arr, arr + 10);

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