我想我明白這一點。但是有沒有辦法讓這個更簡單？

Question

我在C++初學者，我碰到這個代碼就來了：

#include <iostream> 
using namespace std; 

int main() 
{ 
    const long feet_per_yard = 3; 
    const long inches_per_foot = 12; 
    double yards = 0.0;      // Length as decimal yards 
    long yds = 0;        // Whole yards 
    long ft = 0;        // Whole feet 
    long ins = 0;        // Whole inches 
    cout << "Enter a length in yards as a decimal: "; 
    cin >> yards;        // Get the length as yards, feet and inches 
    yds = static_cast<long>(yards); 
    ft = static_cast<long>((yards - yds) * feet_per_yard); 
    ins = static_cast<long>(yards * feet_per_yard * inches_per_foot) % inches_per_foot; 
    cout<<endl<<yards<<" yards converts to "<< yds <<" yards "<< ft <<" feet "<<ins<<" inches."; 
    cout << endl; 
    return 0; 
} 

它的工作原理像您期望的，但我不喜歡所有的類型轉換業務。所以我改變了這本：

#include <iostream> 
using namespace std; 

int main() 
{ 
    long feet_per_yard = 3; 
    long inches_per_foot = 12; 
    long yards = 0.0; 

    long yds = 0;        // Whole yards 
    long ft = 0;        // Whole feet 
    long ins = 0;        // Whole inches 
    cout << "Enter a length in yards as a decimal: "; 
    cin >> yards;        // Get the length as yards, feet and inches 
    yds = yards; 
    ft = (yards - yds) * feet_per_yard; 
    ins = (yards * feet_per_yard * inches_per_foot) % inches_per_foot; 

    cout<<endl<<yards<<" yards converts to "<< yds <<" yards "<< ft <<" feet "<<ins<<" inches."; 
    cout << endl; 


    return 0; 
} 

這當然是因爲「長」沒有像「雙重」確實，十進制值權並不像預期的那樣？

但是，如果我將每個值更改爲'double'類型，那麼％不會與'double'一起使用。有沒有辦法讓這更容易？我聽說過fmod（），但CodeBlock IDE似乎無法識別fmod（）？

此外，我嘗試'浮動'，它似乎也不'浮動'工作。那麼，％工作的變量類型是什麼？我在哪裏可以找到這個參考？

Answer 1

看std::fmod，這是從C.

Answer 2

繼承就宣佈一切爲雙然後你就不需要投。

使用雙數更合理，因爲雙腳的數量是連續數量。

您也可以投在你的表達式，如：

int daysperweek = 7; 
double val = daysperweek * 52.0; // using 52.0 will use implicit conversion