C++ 列表处理 : initializing min to first value of list

Question

我的代码存在的问题是最小值始终为 0。原因是因为我没有正确地将它初始化为“random.txt”的第一个值。我该怎么做？

这是我的代码:

using namespace std;

int main()
{

    ifstream inputFile;
    //open file
    inputFile.open("random.txt");
    int numCount = 0;
    int number, max, min, i, x;
    double average, sum;

    while(inputFile >> number)
    {
        for (i = 0; i < numCount; i++)
        {
            x = number;
            if (x < min)
            {
                min = x;
            }
            else if (x > max)
            {
                max = x;
            }
        }

        numCount++;
        sum = number + sum;
    }
    if (numCount > 0)
    {
        average = sum/numCount;
    }

    inputFile.close();

    cout << "Number of numbers is: " << numCount << endl;
    cout << "Sum of numbers is: " << sum << endl;
    cout << "Average of numbers is: " << average << endl;
    cout << "Max of numbers is: " << max << endl;
    cout << "Min of numbers is: " << min << endl;

    return 0;
}

Answer 1

将 min 初始化为可能的最大值，将 max 初始化为可能的最小值。

喜欢

int min = std::numeric_limits<int>::max();
int max = std::numeric_limits<int>::min();

参见 here for a reference of std::numeric_limits .

---

正如 WhozCraig 在对此答案的评论中所暗示的那样，如果文件中的数字越来越低，并且没有任何值大于以前的值(value)。

您可能想要执行 WhozCraig 在评论中建议的操作，或者更改为两个单独的 if 语句。

---

示例

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

int main()
{
    std::ifstream inputFile("random.txt");
    int number, max=0, min=0;
    int numCount = 0;
    double average=0, sum=0;

    if (inputFile >> number)
    {
        min = max = number;
        numCount = 1;
        while(inputFile >> number)
        {
            if (number < min)
                min = number;
            else if (number > max)
                max = number;

            sum += number;
            ++numCount;
        }

        average = static_cast<double>(sum)/numCount;
    }

    cout << "Number of numbers is: " << numCount << endl;
    cout << "Sum of numbers is: " << sum << endl;
    cout << "Average of numbers is: " << average << endl;
    cout << "Max of numbers is: " << max << endl;
    cout << "Min of numbers is: " << min << endl;

    return 0;
}