如何調用數組中的值並更改數組中的值？

Question

class DataStorage{ 
         // 0 1 2 3 4  5 6 7 8 
string Data[20][4]={{"Wee","50","1","First"},{"Wee","22","2","First"}, 
         // 9 10 11 12  13 14 15 16 
        {"Jason","26","3","First"},{"Krappa","12","4","First"}, 
         // 17 18 19 20  21 22 23 24 
        {" "," ","5","First"},{" "," ","6","Economy"}, 
         //25 26 27 28  29 30 31 32 
        {"Kappa","15","7","Economy"},{"Eraser","17","8","Economy"}, 
         //33 34 35 36  37 38 39 40 
        {" "," ","9","Economy"},{"Morty"," ","10","Economy"}, 
         //41 42 43 44  45 46 47 48 
        {"Rick"," ","11","Economy"},{"Amanda","10","12","Economy"}, 
         //49 50 51 52  53 54 55 56 
        {"Lee","","13","Economy"},{"MingLee"," ","14","Economy"}, 
         //57 58 59 60  61 62 63 64 
        {"Beauty"," ","15","Economy"},{"S4head"," ","16","Economy"}, 
         //65 66 67 68  69 70 71 72 
        {"Ivan"," ","17","Economy"},{"Dex"," ","18","Economy"}, 
         //73 74 75 76  77 78 79 80 
        {"Chua"," ","19","Economy"},{"Haha"," ","20","Economy"},}; 
}; 
int main(){ 

} 

如何調用數組中的值並更改數組中的值？我是否需要製作一些函數來從輸入中獲取值並將其傳遞到類中的變量並將其設置到我的數組中？

Answer 1

我不確定你在問什麼，當你說How do I call the value in array and change the value in array?，但我想你問你如何改變數組元素的值。

要修改數組元素，可以將數組的索引分配給要更改數組元素的元素;然而，請記住，C++數組是0-index arrays含義，當你開始計數它們的元素爲0，例如，如果你想有Data作爲DataStorage類成員下面的代碼修改元件在索引5. Live preview

#include <iostream> 

int array[10] = {1, 5, 33, 7, -23, 2, 8, 54, 19, 2}; 

int main() { 
    std::cout << array[5] << std::endl; 

    array[5] = 100; // Set the value of the element at index 5 to 100 

    std::cout << array[5] << std::endl; 

    return 0; 
} 

Answer 2

你必須在成員初始化列表中初始化它。我也強烈建議使用抽象陣列，如std::array。這允許通過at()函數使用邊界檢查訪問。然後您可以訪問Data並更改其內容。

#include <array> 
#include <iostream> 
#include <string> 

class DataStorage 
{ 
public: 
    std::array<std::array<std::string,4>,20> Data; 
    DataStorage() : Data({{ 
       {{"Wee","50","1","First"}}, 
       {{"Wee","22","2","First"}}, 
       {{"Jason","26","3","First"}}, 
       {{"Krappa","12","4","First"}}, 
       {{" "," ","5","First"}}, 
       {{" "," ","6","Economy"}}, 
       {{"Kappa","15","7","Economy"}}, 
       {{"Eraser","17","8","Economy"}}, 
       {{" "," ","9","Economy"}}, 
       {{"Morty"," ","10","Economy"}}, 
       {{"Rick"," ","11","Economy"}}, 
       {{"Amanda","10","12","Economy"}}, 
       {{"Lee","","13","Economy"}}, 
       {{"MingLee"," ","14","Economy"}}, 
       {{"Beauty"," ","15","Economy"}}, 
       {{"S4head"," ","16","Economy"}}, 
       {{"Ivan"," ","17","Economy"}}, 
       {{"Dex"," ","18","Economy"}}, 
       {{"Chua"," ","19","Economy"}}, 
       {{"Haha"," ","20","Economy"}} 
      }}) {} 
}; 

int main() 
{ 
    DataStorage d; 
    std::cout << d.Data.at(10).at(2) << '\n'; // prints 11 
    d.Data.at(10).at(2) = "1729"; 
    std::cout << d.Data.at(10).at(2) << '\n'; // prints 1729 
}