CODEWITHSUNDEEP
cstringenumstypedef
J_code
J_code

Reputation: 335

Initialize typedef enum to string

Is their a simple way to initialize a typedef enum to a string in C? For example, I would like to initialize the following typedef enum to its string counterpart:

typedef enum 
{ 
    ADD, 
    PLUS, MINUS, MUL, DIV, MOD, 
    AND, OR, NOT, 
    BROKEN_FOO
} foo;

Just like how one initializes any string in C (char* foo = "+"), how could I initialize each member of foo to its string counterpart? e.g. MINUS = "-" etc. I know that each member is represented as an int, but I'm not sure how to go about this, given that each member is represented as an int.

Upvotes: 1

Views: 1801

Answers (2)

Neil
Neil

Reputation: 1922

An alternative that ensures that the symbol aligns with the enum,

#include <stdio.h>

#define OPS \
    X(ADD, +), \
    X(PLUS, +), \
    X(MINUS, -), \
    X(MUL, *), \
    X(DIV, /), \
    X(MOD, %), \
    X(AND, &), \
    X(OR, |), \
    X(NOT, ^)

#define X(a, b) a
enum Foo { OPS };
#undef X

#define X(a, b) #b
static const char *const foo_strings[] = { OPS };
#undef X

static const unsigned foo_size = sizeof foo_strings / sizeof *foo_strings;

#define X(a, b) #a
static const char *const foo_title[] = { OPS };
#undef X

int main(void) {
    unsigned foo;
    for(foo = 0; foo < foo_size; foo++)
        printf("%s: %s\n", foo_title[foo], foo_strings[foo]);
    printf("DIV: %s.\n", foo_strings[DIV]);
    return 0;
}

Upvotes: 2

Stephan Lechner
Stephan Lechner

Reputation: 35154

Enums are represented as integral values, so you cannot assign values of type char*. You could, however, maintain a separate array of strings corresponding to the enum-values:

typedef enum
{
    ADD = 0,
    PLUS = 1, MINUS = 2, MUL = 3, DIV = 4, MOD = 5,
    AND = 6, OR = 7, NOT = 8,
    BROKEN_FOO = 9
} foo;

const char* fooStrings[] = {
   "+","+","-","*","/","%","&","|","^",NULL
};

int main() {

    printf("OR (%d): %s\n", OR, fooStrings[OR]);
}

Upvotes: 2

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