Language: C C++ D Haskell Lua OCaml PHP Perl Plain Text Python Ruby Scheme Tcl #define COG1_TEETH 4 #define COG2_TEETH 25 #define COG3_TEETH 4 #define BASE 1584 int isleap(int year); int main(void) { int year; //printf("Please enter a year\n"); year = 2000; //if (scanf("%d", &year) == 1) { printf("%d is %s\n", year, isleap(year) ? "a leap year" : "not a leap year"); //} else // fputs("Input error", stdout); return 0; } int isleap(int year) { unsigned a, b, c; unsigned i; if (year < BASE) return 0; /* Not Gregorian year */ a = 0; b = COG2_TEETH - COG1_TEETH; c = COG3_TEETH - 1; i = year - BASE; while (i--) { if (++a == COG1_TEETH) { a = 0; if (++b == COG2_TEETH) { b = 0; if (++c == COG3_TEETH) c = 0; } } } return !b ? !a && !c : a == 0; } Private [?] Run code Submit