将文件中的多个输入分隔为偶数或奇数 [英] Separating multiple inputs from a file into even or odd

问题描述

我需要从文件中抽取200个随机数，将其分为偶数和奇数，并使它们的偶数或奇数部分从最低到最高显示.

I need to take 200 randomizes numbers from a file, separate them into even and odd, and make them show up from lowest to highest in their even or odd parts.

从这里我得到了将它变成偶数和奇数的代码，但是原始的方法是10而不是200，并让用户输入数字.

I got the code for making it into even and odd from here but the original way had 10 instead of 200 and made the user input the numbers.

我对此进行了重新设计，但是得到了相同编号的重复，然后读取了抛出Exception的错误:写入写入冲突，在奇数[oddcnt ++] = arr [i]附近有一个标记.

I reworked it into this but I get a repeat of the same number then an error that reads Exception thrown: write access violation with a mark near the odd[oddcnt++] = arr[i];

到目前为止我的代码

#include <iostream>
#include <fstream>
using namespace std;

class Random
{
private:
    int x, arr[200], even[200], odd[200], evncnt = 0, oddcnt = 0, i;
public:
    void readFile();
};
void Random::readFile()
{
    fstream File("Random.txt");
    if (File.is_open())
    {
        while(File >> x)
        {
            for (i = 0; i < 200; i++)
            {
                arr[i] = x;
            }
            for (i = 0; i < 200; i++)
            {
                if (arr[i] % 2 == 0)
                {
                    even[evncnt++] = arr[i];
                }
                else
                {
                    odd[oddcnt++] = arr[i];
                }
            }
            cout << "\n The even numbers are: ";
            for (i = 0; i < evncnt; i++)
            {
                cout << even[i] << "";
            }
            cout << "\n The odd numbers are: ";
            for (i = 0; i < oddcnt; i++)
            {
                cout << odd[i] << "";
            }
        }
        File.close();
    }
}

int main()
{
    Random file;
    file.readFile();
    system("pause");
    return 0;
}

推荐答案

约翰已经给出了答案.一切都很好.

The answer is given already by John. So everything OK.

此外，我想向您展示现代C ++的强大功能.尤其是使用算法时.您可以编写非常精美的解决方案.

Additionally, I would like to show you the power of modern C++. Especially with using algorithms. You can write very elegant solutions.

没有循环，只有几个变量.

Thers is no loop and only vey few variables.

您当然不会复制和粘贴它，因为您不会完全理解它.但这应该为您提供一个想法，该问题如何被分析，设计和编码.

You will of course not copy and paste it, because you will not understand it fully. But it should give you an idea how such a problem could be analysed, then designed, and then coded.

#include <iostream>
#include <fstream>
#include <algorithm>
#include <iterator>
#include <vector>
#include <string>

class Random {
    std::vector<int> values{};
public:
    void readFile(const std::string& fileName);
    void printOdds();
    void printEvens();
};

void Random::readFile(const std::string& fileName) {

    // Open file and check, if it could be opened
    if (std::ifstream inputFileStream(fileName); inputFileStream) {

        // Clear old content in our class
        values.clear();

        // Copy the contents from the vile into our vector
        std::copy(std::istream_iterator<int>(inputFileStream), {}, std::back_inserter(values));

        // sort the values
        std::sort(values.begin(), values.end());
    }
    else {  // File could not be opened
        std::cerr << "\n*** Error: File could not be opened: " << fileName << "\n\n";
    }
}
// Copy all odd values to std::cout
void Random::printOdds() {
    std::copy_if(values.begin(), values.end(), std::ostream_iterator<int>(std::cout, " "), [](const int i) { return (i % 2) != 0; });
    std::cout << "\n\n";
}

// Copy all even values to std::cout
void Random::printEvens() {
    std::copy_if(values.begin(), values.end(), std::ostream_iterator<int>(std::cout, " "), [](const int i) { return (i % 2) == 0; });
    std::cout << "\n\n";
}

// Driver code
int main() {

    Random r;
    r.readFile("r:\\random.txt");
    r.printEvens();
    r.printOdds();

    return 0;
}

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