Go back to Richel Bilderbeek's homepage.
Go back to Richel Bilderbeek's C++ page.
GetSumProperDivisors is a math code snippet to determine if a number is perfect.
#include <cassert> //--------------------------------------------------------------------------- ///GetSumProperDivisors returns the sum of all proper divisors of x ///From http://www.richelbilderbeek.nl/CppGetSumProperDivisors.htm int GetSumProperDivisors(const int x) { assert(x > 0); int sum = 0; const int j = (x / 2) + 1; for (int i=1; i!=j; ++i) { //Is i a proper divisor of x? if (x % i == 0) { sum+=i; } } return sum; } //--------------------------------------------------------------------------- ///IsPerfectNumber determines if x is a perfect number ///From http://www.richelbilderbeek.nl/CppIsPerfectNumber.htm bool IsPerfectNumber(const int x) { return (GetSumProperDivisors(x) == x); } //--------------------------------------------------------------------------- int main() { assert(!IsPerfectNumber( 1)); assert(!IsPerfectNumber( 2)); assert(!IsPerfectNumber( 3)); assert(!IsPerfectNumber( 4)); assert(!IsPerfectNumber( 5)); assert( IsPerfectNumber( 6)); assert(!IsPerfectNumber( 7)); assert(!IsPerfectNumber( 8)); assert(!IsPerfectNumber( 9)); assert(!IsPerfectNumber(10)); assert(!IsPerfectNumber(11)); assert(!IsPerfectNumber(12)); assert(!IsPerfectNumber(13)); assert(!IsPerfectNumber(14)); assert(!IsPerfectNumber(15)); assert(!IsPerfectNumber(16)); assert(!IsPerfectNumber(17)); assert(!IsPerfectNumber(18)); assert(!IsPerfectNumber(19)); assert(!IsPerfectNumber(20)); assert(!IsPerfectNumber(21)); assert(!IsPerfectNumber(22)); assert(!IsPerfectNumber(23)); assert(!IsPerfectNumber(24)); assert(!IsPerfectNumber(25)); assert(!IsPerfectNumber(26)); assert(!IsPerfectNumber(27)); assert( IsPerfectNumber(28)); assert(!IsPerfectNumber(29)); assert(!IsPerfectNumber(30)); assert(!IsPerfectNumber(31)); assert(!IsPerfectNumber(32)); assert(!IsPerfectNumber(33)); assert(!IsPerfectNumber(34)); assert(!IsPerfectNumber(35)); assert(!IsPerfectNumber(36)); }
