Add example of rollover behavior

doc/modules/ROOT/pages/examples.adoc

@@ -145,6 +145,35 @@ Match: true
 ----
 ====
 
+[#examples_rollover]
+== Rollover Behavior
+
+.This https://github.com/cppalliance/int128/blob/develop/examples/rollover.cpp[example] demonstrates the rollover behavior of both the unsigned and signed type
+====
+[source, c++]
+----
+include::example$rollover.cpp[]
+----
+
+.Expected Output
+[listing]
+----
+=== uint128_t behavior ===
+Max of uint128_t: 340282366920938463463374607431768211455
+Max + 1U: 0
+
+Min of uint128_t: 0
+Min - 1U: 340282366920938463463374607431768211455
+
+=== int128_t behavior ===
+Max of int128_t: 170141183460469231731687303715884105727
+Max + 1: -170141183460469231731687303715884105728
+
+Min of int128_t: -170141183460469231731687303715884105728
+Min - 1: 170141183460469231731687303715884105727
+----
+====
+
 [#examples_bit]
 == Bitwise Functions (<bit>)
 

examples/rollover.cpp

@@ -0,0 +1,38 @@
+// Copyright 2025 Matt Borland
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+//
+// This example demonstrates the rollover behavior for both signed and unsigned int128
+
+#include <boost/int128.hpp>
+#include <iostream>
+#include <iomanip>
+#include <limits>
+
+int main()
+{
+    using boost::int128::uint128_t;
+    using boost::int128::int128_t;
+
+    constexpr uint128_t max_unsigned_value {std::numeric_limits<uint128_t>::max()};
+    constexpr uint128_t min_unsigned_value {std::numeric_limits<uint128_t>::min()};
+
+    std::cout << "=== uint128_t behavior ===" << std::endl;
+
+    std::cout << "Max of uint128_t: " << max_unsigned_value << '\n'
+              << "Max + 1U: " << max_unsigned_value + 1U << "\n\n";
+
+    std::cout << "Min of uint128_t: " << min_unsigned_value << '\n'
+              << "Min - 1U: " << min_unsigned_value - 1U << "\n\n";
+
+    constexpr int128_t max_signed_value {std::numeric_limits<int128_t>::max()};
+    constexpr int128_t min_signed_value {std::numeric_limits<int128_t>::min()};
+
+    std::cout << "=== int128_t behavior ===" << std::endl;
+
+    std::cout << "Max of int128_t: " << max_signed_value << '\n'
+              << "Max + 1: " << max_signed_value + 1 << "\n";
+
+    std::cout << "\nMin of int128_t: " << min_signed_value << '\n'
+              << "Min - 1: " << min_signed_value - 1 << '\n' << std::endl;
+}

test/Jamfile

@@ -98,6 +98,7 @@ run ../examples/charconv.cpp ;
 run ../examples/fmt_format.cpp ;
 run ../examples/cstdlib.cpp ;
 run ../examples/numeric_algorithms.cpp ;
+run ../examples/rollover.cpp ;
 
 run limits_link_1.cpp limits_link_2.cpp limits_link_3.cpp ;