c++ - 编辑：根据偶数和奇数元素将数组拆分为两个

Question

我想编写这个程序来从用户那里读取元素的数量和一个列表，打印两个数组，一个用于偶数，一个用于奇数，并显示第一个数组中零的数量。

我纠正了错误，现在没有错误但输出错误。这是代码：

#include <cstdlib>
#include <iostream>
#include <iomanip>

using namespace std;

// Function prototypes
int count(const int list[],  int size, int & odd_num, int & even_num);
void split(const int list[], int size, int list_even[], int even_num, int list_odd[], int odd_num );
void print_list(int array[], int length);

int main()
{
  int size; // llength of the array, user input
  int zero_num; // number of zeros
  int even_num;
  int odd_num;
  int * list; // array to store the user inputs

  // Prompt and read number of elements from the user into the variable size
  cout << "Enter number of elements: ";
  cin >> size;

  // Create a new array of size length and assign it to variable list
  list = new int [size];

  // Prompt and read the elements from the user
  cout << "Enter list: "<<endl;
  for (int i=0; i<size; i++) 
    {
      cin>> list[i];
    }

  // Call function count and save its return value in variable num_zero
  zero_num = count(list,size,odd_num,even_num);

  // allocate an array for even numbers
  int * list_even;
  list_even = new int [even_num];

  // allocate an array for odd numbers
  int * list_odd;
  list_odd= new int [odd_num];

  //

  split(list, size, list_even, even_num, list_odd, odd_num);
  cout << "Even elements: ";
  print_list(list_even, even_num);
  cout<< endl;
  cout << "Odd elements: ";
  print_list(list_odd, odd_num); 
  cout << endl;


  // Delete the lists
  delete[]list;
  delete[]list_even;
  delete[]list_odd;


  return 0;
}

//functions

//function to count the odd and even numbers and th enumber od zeros
int count(const int list[],  int size, int & odd_num, int & even_num)

{
  int i(0); //while loop variable
  int even(0); // variable to count even numbers
  int odd (0); // variable to count odd numbers
  int zero(0); // variable to count zeros
  while (i<size)
     {
       if (list[i] == 0)
     {
       zero++;
     }
       else if (list[i]% 2 ==0)
     {
       even++;
     }
       else 
     {
       odd++;
     }
       i++;
     }
 return  zero;

}

// function to copy odd and even number to seperate arrays
void split(const int list[], int size, int list_even[], int even_num, int list_odd[], int odd_num )
{
  int j(0);
  int k(0);
  while (j<even_num && k<odd_num)
    {
      for (int i(0); i<size; i++)
    {
      if(list[i]%2 == 0)
        {
          list_even[j]= list[i];
          j++;
        }
      if(list[i]%2 == 1)
        {
          list_odd[k]= list[i];
          k++;
        }
    }
    }
}

// function to print an  array
void print_list(int array[], int length)
{
  cout << array << endl;
}

这是输入和输出的示例：

Enter number of elements: 6
Enter list: 
1
2
3
4
5
6
Even elements: 0x988030

Odd elements: 0x7f601e480010

Answer 1

你这样打电话split：

void split(list[], size, list_even[], even_num, list_odd[], odd_num);

这是错的。它是函数声明。应该是（以下两行也有这个问题）

split(list, size, list_even, even_num, list_odd, odd_num);

 

另一个问题是，您正在打印void，cout删除这些cout代码：

split(list, size, list_even, even_num, list_odd, odd_num);
print_list(list_even, even_num);
print_list(list_odd, odd_num);

 

最后，要打印一个数组int x[]，您应该通过循环对项目进行迭代，所以这段代码是错误的：

void print_list(int array[], int length)
{
    cout << "Even elements: " << array[] << endl;
}

改用这个：

void print_list(int array[], int length)
{
    cout << "Even elements: " << endl;
    for (int i=0; i<length; i++)
    cout << array[i] << " ";
}

 

这是一个工作代码（至少它可以编译）！

---

虽然你已经std::vector忘记了那些硬数组。

Answer 2

void如果您在第 58 行调用 split ，您有一个infront 。删除那里的 void 一词。

Answer 3

删除函数调用中的 void

void split(list[], size, list_even[], even_num, list_odd[], odd_num);

Answer 4

或者您可以使用标准容器和算法：

int main()
{
    std::vector<int> numbers;
    std::size_t count;

    std::cout << "Enter the number of elements:  ";
    std::cin >> count;

    while (numbers.size() < count)
    {
        int i;
        if (std::cin >> i)
        {
            numbers.push_back(i);
        }
        else
        {
            std::cin.clear();
        }
    }

    std::vector<int> evens, odds;
    std::partition_copy(numbers.begin(), numbers.end(), std::back_inserter(evens), std::back_inserter(odds), [](int i)
    {
        return 0 == i % 2;
    });

    std::size_t numZeros = std::count(numbers.begin(), numbers.end(), 0);

    std::cout << "Evens (" << evens.size() << "):  ";
    std::copy(evens.begin(), evens.end(), std::ostream_iterator<int>(std::cout, ", "));
    std::cout << std::endl;

    std::cout << "Odds (" << odds.size() << "):  ";
    std::copy(odds.begin(), odds.end(), std::ostream_iterator<int>(std::cout, ", "));
    std::cout << std::endl;

    return 0;
}