Visualize enum value | 易学教程

问题

How can i visualize the types of food with type enum?

typedef struct cat{
 int code;
 int age;
 float weight;
 enum {kibbles,canned_food,tuna_fish}food;
} cats;

int n,i;

printf("Insert a number: ");
scanf("%d",&n);

cats *cat_arr = calloc(n, sizeof(cats));

for(i = 0;i<n;i++){
    printf("Code: ");
    scanf("%d",&cat_arr[i].code);
    printf("Age: ");
    scanf("%d",&cat_arr[i].age);
    printf("weight: ");
    scanf("%f",&cat_arr[i].weight);
    printf("Food: ");
    scanf("%d",&cat_arr[i].food);
}


for(i=0;i<n;i++){
    if(cat_arr[i].age < 4 && cat_arr[i].weight > avg){
        printf("%d %s",cat_arr[i].code,cat_arr[i].food);   <---- HERE
    }
}

I want insert type of food with numbers and display the name that i assigned with enum.

回答1:

There's no automatic way to get the string equivalent of an enum constant. You'll need to create a mapping of enums to their string equivalents and reference that.

const char *food_names[] = { "kibbles" , "canned_food" ,"tuna_fish" };

...

printf("%d %s", cat_arr[i].code, food_names[cat_arr[i].food]);

回答2:

If you want to do that in a somewhat automated way, you'll need to use some preprocessor-magic:

#define FOOD(X) \
        X(kibbles), \
        X(canned_food), \
        X(tuna_fish)

#define EXPAND_AS_ENUM(a)     a
#define EXPAND_AS_STRING(a)  #a

enum
{
    FOOD(EXPAND_AS_ENUM)
} food;

const char* food_names[] =
{
    FOOD(EXPAND_AS_STRING)
}

This way, you'll get an enum and the corresponding string-array with matching names

回答3:

It's hard to get what you wxactly mean but if you want to get enum name from index then:

struct Type{
    enum Err{
        not_found = 0,
        internet = 1
    }
    std::string get( int index ){
        if(index == 0) return "not_found";
        if(index == 1) return "internet";
    }
};

Then call the get function with index as argument

来源：https://stackoverflow.com/questions/61344384/visualize-enum-value

标签

enums