libstdc++-v3/testsuite/26_numerics/gcd/1.cc

// Copyright (C) 2015-2023 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING3.  If not see
// <http://www.gnu.org/licenses/>.

// { dg-do compile { target c++17 } }

#include <numeric>

#ifndef __cpp_lib_gcd_lcm
# error "Feature-test macro for gcd missing"
#elif __cpp_lib_gcd_lcm != 201606
# error "Feature-test macro for gcd has wrong value"
#endif

using std::gcd;
using std::is_same_v;

static_assert( gcd(1071, 462) == 21, "" );
static_assert( gcd(2000, 20) == 20, "" );
static_assert( gcd(2011, 17) == 1, "GCD of two primes is 1" );
static_assert( gcd(200, 200) == 200, "GCD of equal numbers is that number" );
static_assert( gcd(0, 13) == 13, "GCD of any number and 0 is that number" );
static_assert( gcd(29, 0) == 29, "GCD of any number and 0 is that number" );
static_assert( gcd(0, 0) == 0, "Zarro Boogs found" );

static_assert(gcd(1u, 2) == 1, "unsigned and signed");
static_assert(gcd(9, 6u) == 3, "unsigned and signed");
static_assert(gcd(3, 4u) == 1, "signed and unsigned");
static_assert(gcd(32u, 24) == 8, "signed and unsigned");
static_assert(gcd(1u, -2) == 1, "unsigned and negative");
static_assert(gcd(-21, 28u) == 7, "unsigned and negative");
static_assert(gcd(-3, 4u) == 1, "negative and unsigned");
static_assert(gcd(33u, -44) == 11, "negative and unsigned");
static_assert(gcd(5u, 6u) == 1, "unsigned and unsigned");
static_assert(gcd(54u, 36u) == 18, "unsigned and unsigned");
static_assert(gcd(-5, -6) == 1, "negative and negative");
static_assert(gcd(-50, -60) == 10, "negative and negative");

static_assert( is_same_v<decltype(gcd(1l, 1)), long> );
static_assert( is_same_v<decltype(gcd(1ul, 1ull)), unsigned long long> );