循环遍历包含C中枚举条目的结构

Question

我正在尝试编写一个循环结构并返回枚举变量的方法。所述方法是lookup_transitions()，这是我的代码:(我使用enum作为指向我的函数的指针，因为在这种情况下我不确定如何有效地使用int指针）。

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>


enum ret_codes { ok, fail};
//forward declaration of functions
enum ret_codes s0_state(int);
enum ret_codes s1_state(int);
enum ret_codes s2_state(int);

/* pointer to the functions*/
enum ret_codes (* state[])(int) = 
{
  s0_state,
  s1_state,
  s2_state
};


enum state_codes { s0, s1, s2 };

struct transition {
  enum state_codes src_state;
  enum ret_codes   ret_code;
  enum state_codes dst_state;
};

struct transition state_transitions[] = {
  {s0, ok,     s1},
  {s0, fail,   s0},
  {s1, ok,     s2},
  {s1, fail,   s0}};

//function definitions
//these were previously returning int, changed to enum ret_codes
      enum ret_codes s0_state(int digit){
      puts ("\nState s0 (RESET):");
      puts ("(alarm inactive)");
      puts ("Enter password to arm alarm, or 'e' to cancel: ");     
      if (digit != 5){
        return fail;
      }
      return ok;
    }
    enum ret_codes s1_state(int digit){
      puts ("\nState s1:\n");
      if (digit != 6)
        return fail;
      return ok;
    }
    enum ret_codes s2_state(int digit){
      puts ("\nState s2, (alarm inactive): \n");
      if (digit != 3)
        return fail;
      return ok;
    }

    enum state_codes lookup_transitions(enum state_codes sc, enum ret_codes myRC){
        //should return s0,s1 or s2
        enum state_codes result = sc;
        for (int i = 0; i < sizeof(state_transitions)/sizeof(state_transitions[0]); ++i)
        {
            if (state_transitions[i].src_state == sc && state_transitions[i].ret_code == myRC)
            {
                result =  state_transitions[i].dst_state;
            }
        }
        return result;
    }

    #define S0_STATE s0

    int main(int argc, char *argv[] ){
        int input;

          enum state_codes curr_state = S0_STATE;

          enum ret_codes (* state_fun)(int);
          state_fun = state[curr_state]; //start at s0
          enum ret_codes rc;

          while (true){
            input = getchar();
            if( input != 'e') {
                rc = state_fun(input);
                curr_state = lookup_transitions(curr_state, rc);//should return s0,s1 or s2
            }
            input = getchar();
          }
      puts ("\nProgram completed successfully");
      return 0;
    }

我的lookup_transitions（）方法似乎没有正确迭代数组。你能帮我搞清楚吗？