Question

所以我正在尝试制作一个程序，将一个int数组分成两个，一个用于偶数，一个用于不均匀的int。现在，奇怪的是，如果我只输入偶数或不均匀的数字到基数组，程序工作正常，但如果我输入两者的混合，两个新数组保持的值之一将是随机的，通常是消极的，大数字，任何想法为什么会这样？

#include <iostream>
using namespace std;

void main()
{
    int *a, n, *even_nums = 0, *uneven_nums = 0, counter_even = 0,counter_uneven = 0;
    cout << "How many values does your array have?\n" << endl;
    cin >> n;
    a = new int[n];
    cout << "\nEnter the values in your array:" << endl;
    for (int i = 0; i < n; i++)
    {
        cout << "a[" << i << "] = ";
        cin >> a[i];
        if (a[i] % 2 == 0)
            counter_even++;
        else 
            counter_uneven++;
    }
    if (counter_even == 0)
        cout << "There are no even numbers in your array." << endl;
    else
        even_nums = new int[counter_even];
    if (counter_uneven == 0)
        cout << "There are no uneven numbers in your array." << endl;
    else
        uneven_nums = new int[counter_uneven];
    for (int i = 0; i < n; i++)
    {
        if (a[i] % 2 == 0)
            even_nums[i] = a[i];
        else
            uneven_nums[i] = a[i];
    }
    if (counter_even != 0)
    {
        cout << "\nThe even numbers in your array are:" << endl;
        for (int i = 0; i < counter_even; i++)
            cout << even_nums[i] << " ";
    }
    if (counter_uneven != 0)
    {
        cout << "\nThe uneven numbers in your array are:" << endl;
        for (int i = 0; i < counter_uneven; i++)
            cout << uneven_nums[i] << " ";
    }
    system("PAUSE");
}

Answer 1

在块中

您使用a作为数组even_nums，uneven_nums和even_nums的相同索引。您需要为这些数组使用单独的索引。例如，如果您有n = 10个元素，5个偶数和5个奇数，则uneven_nums和$scope.favorites = ["a", "b", "c", "d"]; $scope.dataCount = 4; $scope.$watchCollection('favorites', function(newFavs, oldFavs) { $scope.dataCount = newFavs.length; });每个只包含5个元素。

Answer 2

在

for (int i = 0; i < n; i++)
{
    if (a[i] % 2 == 0)
        even_nums[i] = a[i];
    else
        uneven_nums[i] = a[i];
}

您对所有阵列使用相同的索引。如果您同时使用even_nums，uneven_nums将小于a，则此功能无效。您将最终写入数组末尾undefined behavior。

您需要做的是为每个数组添加一个索引，每次将元素插入数组时，都会推进该索引。

for (int i = 0, u = 0, e = 0; i < n; i++)
{
    if (a[i] % 2 == 0)
        even_nums[e++] = a[i];
    else
        uneven_nums[u++] = a[i];
}

此外，您使用的是void main()，这不是标准的，不应使用。 int main()和int main(int argc, char** argv)是main()

的标准可接受签名

随机整数出现在程序错误中

2 个答案: