Use of Enum within a Struct

Question

Good evening. I have to do a program where I have to create several elements using the following:

typedef enum {ATRIB, ADD, SUB, MUL, IF_I, PRINT, READ, GOTO_I, LABEL} OpKind;

typedef enum {EMPTY, INT_CONST, STRING} ElemKind;

typedef struct{
     ElemKind kind;
      union{ 
        int val;
        char *name;
        } contents;
} Elem;

typedef struct{
   OpKind op;
   Elem first, second, third;
} Instr;

However, I am failing to see how to assign values to each of the elements of Instr. Can anyone give a simple example of how I can do the assignment? Thank you

Answer 1

Instr is a guy. You have to define a object (a variable) of this type to assign a value.

Instr foo; // foo não inicializado
Instr bar = {0}; // bar inicializado com zeros
Instr baz = {ATTRIB, {EMPTY, {0}}, {INT_CONST, {42}}, {STRING, {-1}}};
Instr quux = { .op = READ }; // C99 designated initializer

foo.second.contents.name = "foo"; // atribuição