c - How to convert literal char hex value into the hex value itself? -

i'm having literal value should stored on unsigned char[64] array. how can convert such values it's hex equivalent?

int main() {      unsigned char arry[1] = { 0xaa }      char* str = "fe"; //i want store 0xfe on arry[0]      arry[0] = 0xfe; // works, have type     arry[0] = 0x + str; //obviously fails      return 0; } 

any pointers?

arr[0] = strtol(str,null,16);  // if 1 entry big enough hold it.