enum.cpp

#include <iostream>
using namespace std;

enum color {WHITE, BLACK, RED, GREEN, BLUE, YELLOW, NUM_COLORS};
enum datatype {TYPE_INT8=1, TYPE_INT16=2, TYPE_INT32=4, TYPE_INT64=8};

struct Point{
    enum datatype type;
    union {
        std::int8_t data8[3];
        std::int16_t data16[3];
        std::int32_t data32[3];
        std::int64_t data64[3];
    };
};

size_t datawidth(struct Point pt)
{
    return size_t(pt.type) * 3;
}

int64_t l1norm(struct Point pt)
{
    int64_t result = 0;
    switch(pt.type)
    {
        case (TYPE_INT8): 
            result = abs(pt.data8[0]) + abs(pt.data8[1]) + abs(pt.data8[2]);
            break;
        case (TYPE_INT16): 
            result = abs(pt.data16[0]) + abs(pt.data16[1]) + abs(pt.data16[2]);
            break;
        case (TYPE_INT32): 
            result = abs(pt.data32[0]) + abs(pt.data32[1]) + abs(pt.data32[2]);
            break;
        case (TYPE_INT64): 
            result = abs(pt.data64[0]) + abs(pt.data64[1]) + abs(pt.data64[2]);
            break;
    }
    return result;
}

int main()
{
    enum color pen_color = RED;
    pen_color = color(3); //convert int to enum
    cout << "We have " << NUM_COLORS << " pens." << endl;
    //pen_color += 1; //error!
    int color_index = pen_color;
    color_index += 1;
    cout << "color_index = " << color_index << endl;

    //declaration and initialization
    struct Point point1 = {.type=TYPE_INT8, .data8={-2,3,4}};
    struct Point point2 = {.type=TYPE_INT32, .data32={1,-2,3}};
    
    cout << "Data width = " << datawidth(point1) << endl;
    cout << "Data width = " << datawidth(point2) << endl;

    cout << "L1 norm = " << l1norm(point1) << endl;
    cout << "L1 norm = " << l1norm(point2) << endl;


    return 0;
}