未初始化数组中的最小值和最大值

Question

任务是取12个月的降雨量存入数组。然后根据收集的数据计算总和、平均值、最小值和最大值。我发现总和和平均值很好。我不知道我的最大值和最小值哪里出错了。

#include <iostream>
using namespace std; 

int main()
{
    //inititalizing variables 
    double rain[13];
    double sum = 0;
    double max = rain[0];
    double min = rain[0];
    int count = 0;
    //string highMonth, lowMonth;

    //inputing rain values for each month 
    for (int i = 1; i < 13; i++)
    {
        cout << "Enter the rainfall (in inches) for month #" << i << ":";
        cin >> rain[13];
        sum = sum + rain[13];
    }

    //finding the max  
    for ( count = 1; count < 13; count++)
    {
        if (rain[count] > max)
        {
            max = rain[count];
        }
    }
    //finding the min 
    for (count = 1; count < 13; count++)
    {
        if (rain[count] < min)
        {
            min = rain[count]; 
        }
    }

    //printing results 
    cout << " The total rainfall for the year is" << sum<<endl; 
    cout << "The average rainfall is: " << sum / 12<<endl; 
    cout << "The month with the highest rainfall was " << max <<  endl;
    cout << "The month with the lowest rainfall was " << min << endl;
    return 0; 
}

Answer 1

// ...
double rain[13]; // uninitialized here
double sum = 0;
double max = rain[0]; // garbage
double min = rain[0]; // garbage
// ...

当 max 和 min 被初始化时，

rain[0] 指向垃圾。在将有意义的数据读入 rain.

后，您应该声明并初始化 max 和 min

Answer 2

这样做：

double max = rain[0];
double min = rain[0];

在未初始化的数组中与在变量 max 和 min，你必须初始化为其他值，数组 rain 也是如此.

下一期是这样的：

for (int i = 1; i < 13; i++)
    {
        cout << "Enter the rainfall (in inches) for month #" << i << ":";
        cin >> rain[13];
        sum = sum + rain[13];
    }

您正试图在数组中的索引 13 处写入，这绝对超出了您的范围..

cin >> rain[i];

"i" 从 0 到 13 独占是正确的

另一方面，您查找最大值和最小值的循环不完整（您循环了 12 次而忽略了索引 0 处的元素）

for ( count = 1; count < 13; count++)

如果你的数组有 13 个元素，你必须这样做

for ( count = 0; count < 13; count++)

Answer 3

首先，您应该检查循环是 cin >> rain[i] 而不是 rain[13]。 min/max 应使用现有值进行初始化。

您的数组未初始化，因此您指向的是无用的值。

您可以这样做：

double max = 0;
double min = std::numeric_limits<double>::max();

Answer 4

我建议在 C++11 中使用 std::array 和基于范围的 for 循环。这样更不容易出错。

#include <array>
#include <iostream>

int main()
{
    //storage variable
    std::array<double,12> rain;

    //inputing rain values for each month
    double sum = 0;
    unsigned i = 0;
    for (auto &p : rain)
    {
        std::cout << "Enter the rainfall (in inches) for month #" << ++i << ": ";
        std::cin >> p;
        sum += p;
    }

    //finding the max
    double max = rain[0];
    for (auto &p : rain)
    {
        if (p > max)
        {
            max = p;
        }
    }

    //finding the min
    double min = rain[0];
    for (auto &p : rain)
    {
        if (p < min)
        {
            min = p;
        }
    }

    //printing results 
    std::cout << "The total rainfall for the year is " << sum << "\n";
    std::cout << "The average rainfall is: " << sum / 12 << "\n"; 
    std::cout << "The month with the highest rainfall was " << max <<  "\n";
    std::cout << "The month with the lowest rainfall was " << min << "\n";
}

或者更好，只需使用 STL。

#include <algorithm>
#include <array>
#include <iostream>

int main()
{
    //storage variable
    std::array<double,12> rain;

    //inputing rain values for each month
    unsigned i = 0;
    for (auto &p : rain)
    {
        std::cout << "Enter the rainfall (in inches) for month #" << ++i << ": ";
        std::cin >> p;
    }

    //finding the min, max, average
    auto max = *std::max_element(std::begin(rain), std::end(rain));
    auto min = *std::min_element(std::begin(rain), std::end(rain));
    auto sum = std::accumulate(std::begin(rain), std::end(rain), double{0.0});

    //printing results 
    std::cout << "The total rainfall for the year is " << sum << "\n";
    std::cout << "The average rainfall is: " << sum / 12 << "\n"; 
    std::cout << "The month with the highest rainfall was " << max <<  "\n";
    std::cout << "The month with the lowest rainfall was " << min << "\n";
}

未初始化数组中的最小值和最大值

Min and Max in Uninitialized Array

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