未初始化阵列中的最小值和最大值

Question

任务是取12个月的雨量并将它们存储到数组中。然后根据收集的数据计算总和，平均值，最小值和最大值。我发现总数和平均数很好。我不知道我的最大和最小值出错了。当max和min初始化

#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

我建议使用std::array和基于范围，适用于C++ 11的循环：

你可以这样做。这种方式不太容易出错。

#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"; 
} 

甚至更​​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"; 
} 

Answer 2

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

rain[0]点垃圾。将有意义的数据读入rain之后，您应该声明并初始化max和min。

Answer 3

这样做：

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

在未初始化数组

是一样的把一些垃圾值在 变量最大和分钟，你必须初始化为其它值，同样的阵列雨。

下一个问题是这样的：

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

你是在这绝对是你的界限的数组中的索引13写，要来试图..

cin >> rain[i]; 

将与正确的事“我“从0到13独家

另一方面，你的循环寻找最大值和最小值是不完整的（你正在循环12次忽略索引0处的元素）

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

如果你的阵列有13种元素，你必须做

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

Answer 4

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

您的数组未初始化，因此您指向无用的值。

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