如何将混合数据类型(int，float，char等)存储在数组中? [英] How can mixed data types (int, float, char, etc) be stored in an array?

问题描述

我想在数组中存储混合数据类型.怎么会这样呢?

I want to store mixed data types in an array. How could one do that?

推荐答案

您可以使数组元素成为有区别的联合，也称为 tagged联合.

You can make the array elements a discriminated union, aka tagged union.

struct {
    enum { is_int, is_float, is_char } type;
    union {
        int ival;
        float fval;
        char cval;
    } val;
} my_array[10];

type成员用于选择应为每个数组元素使用union的哪个成员.因此，如果要在第一个元素中存储int，则可以执行以下操作:

The type member is used to hold the choice of which member of the union is should be used for each array element. So if you want to store an int in the first element, you would do:

my_array[0].type = is_int;
my_array[0].val.ival = 3;

要访问数组的元素时，必须首先检查类型，然后使用联合的相应成员. switch语句很有用:

When you want to access an element of the array, you must first check the type, then use the corresponding member of the union. A switch statement is useful:

switch (my_array[n].type) {
case is_int:
    // Do stuff for integer, using my_array[n].ival
    break;
case is_float:
    // Do stuff for float, using my_array[n].fval
    break;
case is_char:
    // Do stuff for char, using my_array[n].cvar
    break;
default:
    // Report an error, this shouldn't happen
}

由程序员决定确保type成员始终与union中存储的最后一个值相对应.

It's left up to the programmer to ensure that the type member always corresponds to the last value stored in the union.

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