Some difference between struct and union
In modern programming, C language is less likely for most of companies,

but it is worth learning some nasty features in C
#include 
#include 

    union fox{
        int num;
        char ch;
    };

    union foo{
        int num;
        int age;
    };

    struct Point{
        int x;
        int y;
    } point;

    int main () {
        union foo f = {2, 200};
        printf("f.num=%d\n", f.num); // => 2
        printf("f.age=%d\n", f.age); // => 2

        union fox fo = {'a', 'z'};
        printf("fo.num=%d\n", fo.num); // => 97
        printf("fo.ch=%c\n", fo.ch);   // => 'a'

        struct Point point = {1, 2};

        printf("point.x=%d\n", point.x); // => 1
        printf("point.y=%d\n", point.y); // => 2

       return(0);
    }