Check if a value is defined in an C enum?
The easiest way to do this is:
enum {
MODE_A,
MODE_B,
MODE_C
};
int modeValid(int mode)
{
int valid = 0;
switch(mode) {
case MODE_A:
case MODE_B:
case MODE_C:
valid = 1;
};
return valid;
}
void setMode(int mode)
{
if (modeValid(mode)) {
// Blah, blah
}
}
int main(void)
{
setMode(1); // Okay
setMode(500); // Error
}
Not to the best of my knowledge. An enum in C is just a cleaner alternative to a series of
#define A 0x2E
statements.
If the enum is large and its values happen to be continuous, declare min/max constants and compare to those:
enum { E_MIN = 0x2E, A = 0x2E, B = 0x23, C = 0x40 ..., E_MAX=0x100};
if(x >= MIN && x <= MAX)
ItsInEnum();
This is kind of a modified version of your question, but depending on what you're doing, something like this might work:
enum {A,B,C};
const int E[] = {0x2E,0x23,0x40};
// Or:
// enum { A = 0x2E, B = 0x23, C = 0x40 };
// const int E[] = {A,B,C};
int isEnum(int x)
{
for(int i=0; i<(sizeof(E)/sizeof(*E)); i++)
{
if(E[i] == x){ return 1; }
}
return 0;
}
int main(void)
{
printf("Value of A: 0x%02x\n", E[A]);
// Or:
// printf("Value of A: 0x%02x\n", A);
printf("isEnum(0x2e): %s\n", isEnum(0x2e) ? "true" : "false");
printf("isEnum(0x2f): %s\n", isEnum(0x2f) ? "true" : "false");
}
which outputs
Value of A: 0x2e isEnum(0x2e): true isEnum(0x2f): false
EDIT: TJD beat me to it, and his suggestion of using a sorted array and doing binary search would decrease your search time from n to log(n).