将char *转换为枚举值的有效方法
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在C语言中，我可以使用预处理器将ѭ0转换为等效的字符串。
但是，有什么巧妙的技巧可以将
char*
enum
strcmp
enum
没有找到相关结果
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素汞读
#include <stdio.h> #include <string.h> #include <stdlib.h> /*** BEGIN HACK ***/ #define CREATEENUM(name, first, ...) \\ typedef enum { first = 0, __VA_ARGS__ } name; \\ char name##_s[] = #first \", \" #__VA_ARGS__; #define TOSTR(x) #x #define TOENUM(name, x) ((name) _toenum(name##_s, x)) long _toenum(char *enum_s, const char *x) { long i = 0; size_t len = strlen(enum_s); char *copy = (char*) malloc(sizeof(char) * (len + 1)); strncpy(copy, enum_s, len); copy[len] = \'\\0\'; char *saveptr = NULL; char *s = strtok_r(copy, \", \", &saveptr); do { if (strcmp(s, x) == 0) { free(copy); return i; } i++; } while((s = strtok_r(NULL, \", \", &saveptr)) != NULL); free(copy); return -1; } /*** END HACK ***/ // create enum with the name \"super\" CREATEENUM(super, COOL, AWESOME, UBER, JON_SKEET ) int main(int argc, char *argv[]) { printf(\"%d\\n\", TOENUM(super, \"JON_SKEET\")); // 3 printf(\"%d\\n\", TOENUM(super, \"EXTREME\")); // -1 (not found) printf(\"%d\\n\", TOENUM(super, \"COOL\")); // 0 printf(\"%s\\n\", TOSTR(AWESOME)); // AWESOME return 0; }补蹲农界维
enum colors { unknown = 0, red, blue, black, yellow }; struct enumtypes { colors color; char* str; }; struct enumtypes array[] = { {red,\"red\"}, {blue,\"blue\"} // etc for each enum type }; // function to convert string to enum type colors cvt(const char* str) { const int sz = sizeof(array) / sizeof(array[0]); for(int i = 0; i < sz; i++) { if(strcmp(array[i].str, str) == 0) return array[i].color; } return unknown; }号拳藐孔妇
#include <string.h> /* Find string in mapping. Return -1 if not found. */ int map_string_to_int(char *map[], int count, char *string) { for (int i = 0; i < count; ++i) { if (strcmp(map[i], string) == 0) return i; } return -1; } /* Map int to string. Return NULL if not found. */ char *map_int_to_string(char *map[], int count, int i) { if (i < 0 || i >= count) return NULL; return map[i]; } /* Add new string to mapping. Return its unique id. Return existing id if string was in mapping already. Caller is responsible to make sure there\'s room. Caller is responsible for making sure string does not get de-allocated. */ int map_add(char *map[], int *count, char *string) { int i; i = map_string_to_int(map, *count, string); if (i == -1) { i = *count; map[i] = string; ++(*count); } return i; } /* A main program for testing, not actually part of the library. */ #include <stdio.h> #define N 1024 int main(void) { char *map[N]; int count; map_add(map, &count, \"Monday\"); map_add(map, &count, \"Tuesday\"); map_add(map, &count, \"Thursday\"); map_add(map, &count, \"Wednesday\"); map_add(map, &count, \"Friday\"); map_add(map, &count, \"Sunday\"); map_add(map, &count, \"Saturday\"); for (int i = 0; i < count; ++i) printf(\"[%d] = %s\\n\", i, map_int_to_string(map, count, i)); printf(\"Monday is %d\\n\", map_string_to_int(map, count, \"Monday\")); return 0; }链眷克袒姜
#include <stdio.h> enum Weekdays { Sun = \'S\' + \'u\' + \'n\', Mon = \'M\' + \'o\' + \'n\', Tue = \'T\' + \'u\' + \'e\', Wed = \'W\' + \'e\' + \'d\', Thu = \'T\' + \'h\' + \'u\', Fri = \'F\' + \'r\' + \'i\', Sat = \'S\' + \'a\' + \'t\' }; int main(void) { char tmp[10]; printf(\"Enter day of the week: \"); fflush(stdout); if (fgets(tmp, sizeof tmp, stdin)) { enum Weekdays enumvalue = tmp[0] + tmp[1] + tmp[2]; switch (enumvalue) { default: printf(\"Ohoh\\n\"); break; case Sun: printf(\"Sun: %d\\n\", Sun); break; case Mon: printf(\"Mon: %d\\n\", Mon); break; case Tue: printf(\"Tue: %d\\n\", Tue); break; case Wed: printf(\"Wed: %d\\n\", Wed); break; case Thu: printf(\"Thu: %d\\n\", Thu); break; case Fri: printf(\"Fri: %d\\n\", Fri); break; case Sat: printf(\"Sat: %d\\n\", Sat); break; } } return 0; }醒荒捆府绣
车料
的示例：typedef enum { MyEnum_foo, MyEnum_bar, MyEnum_baz, } MyEnum; /** * M -> y -> E -> n -> u -> m -> _ -> f -> o -> o * -> b -> a -> r * -> z */ MyEnum parse_MyEnum(const char *str) { int state = 0; MyEnum result; if (str == 0) { /* handle null pointer error */ } for ( ; ; ) { char c = *str++; switch (state) /* case sensitive parse */ { case 0: /* we could jump to state 7 with the appropriate check here but I won\'t :) */ switch (c) { case \'M\': state = 1; break; default: goto error_state; } break; case 1: /* M */ switch (c) { case \'y\': state = 2; break; default: goto error_state; } break; case 2: /* My */ switch (c) { case \'E\': state = 3; break; default: goto error_state; } break; case 3: /* MyE */ switch (c) { case \'n\': state = 4; break; default: goto error_state; } break; case 4: /* MyEn */ switch (c) { case \'u\': state = 5; break; default: goto error_state; } break; case 5: /* MyEnu */ switch (c) { case \'m\': state = 6; break; default: goto error_state; } break; case 6: /* MyEnum */ switch (c) { case \'_\': state = 7; break; default: goto error_state; } break; case 7: /* MyEnum_ */ switch (c) { case \'f\': state = 8; break; case \'b\': state = 11; break; default: goto error_state; } break; case 8: /* MyEnum_f */ switch (c) { case \'o\': state = 9; break; default: goto error_state; } break; case 9: /* MyEnum_fo */ switch (c) { case \'o\': state = 10; break; default: goto error_state; } break; case 10: /* MyEnum_foo */ switch (c) { case \'\\0\': result = MyEnum_foo; goto accept_state; default: goto error_state; } break; case 11: /* MyEnum_b */ switch (c) { case \'a\': state = 12; break; default: goto error_state; } break; case 12: /* MyEnum_ba */ switch (c) { case \'r\': state = 13; break; case \'z\': state = 14; break; default: goto error_state; } break; case 13: /* MyEnum_bar */ switch (c) { case \'\\0\': result = MyEnum_bar; goto accept_state; default: goto error_state; } break; case 14: /* MyEnum_baz */ switch (c) { case \'\\0\': result = MyEnum_baz; goto accept_state; default: goto error_state; } break; default: /* we shouldn\'t be here */ assert(0); } } error_state: /* handle error */ result = (MyEnum)-1; accept_state: return result; }