diff --git a/Makefile b/Makefile
index f34f88a..bd18f16 100755
--- a/Makefile
+++ b/Makefile
@@ -28,6 +28,11 @@ sheet04:
 	chmod +x build/sheet04
 	build/sheet04
 
+cint:
+	${BUILD_CMD} src/cint.cpp -o build/cint
+	chmod +x build/cint
+	build/cint
+
 pizza:
 	${BUILD_CMD} src/pizza.cpp -o build/pizza
 	chmod +x build/pizza
diff --git a/src/cint.cpp b/src/cint.cpp
new file mode 100644
index 0000000..349a3e3
--- /dev/null
+++ b/src/cint.cpp
@@ -0,0 +1,135 @@
+//===----------------------------------------------------------------------===//
+//
+// Philipp Schubert
+//
+//    Copyright (c) 2017 - 2021
+//    Secure Software Engineering Group
+//    Heinz Nixdorf Institute
+//    Paderborn University
+//    philipp.schubert@upb.de
+//
+//===----------------------------------------------------------------------===//
+
+#include <algorithm>
+#include <exception>
+#include <iostream>
+#include <limits>
+
+const int MIN_MAX_DIFF = std::abs(std::abs(std::numeric_limits<int>::min())-std::abs(std::numeric_limits<int>::max()));
+class sint {
+ private:
+	int value;
+
+ public:
+	sint() : value(0) {}
+	sint(int i) : value(i) {}
+	~sint() = default;
+	sint(const sint &s) = default;
+	sint &operator=(const sint &s) = default;
+	sint(sint &&s) = default;
+	sint &operator=(sint &&s) = default;
+	int getUnderlyingValue() const noexcept { return value; }
+	friend sint operator+(sint lhs, sint rhs)
+	{
+		int result;
+			if(__builtin_sadd_overflow(lhs.getUnderlyingValue(), rhs.getUnderlyingValue(), &result))
+			{
+				throw std::overflow_error("addition overflow");
+			}
+			return result;
+	}
+	friend sint operator-(sint lhs, sint rhs)
+	{
+		int result;
+			if(__builtin_ssub_overflow(lhs.getUnderlyingValue(), rhs.getUnderlyingValue(), &result))
+			{
+				throw std::overflow_error("subtraction overflow");
+			}
+			return result;
+	}
+
+	friend sint operator*(sint lhs, sint rhs)
+	{
+		int result;
+			if(__builtin_smul_overflow(lhs.getUnderlyingValue(), rhs.getUnderlyingValue(), &result))
+			{
+				throw std::overflow_error("multiplication overflow");
+			}
+			return result;
+	}
+
+	// friend sint operator/(sint lhs, sint rhs)
+	// {
+	// 	int result;
+	// 		if(__builtin_sdiv_overflow(lhs.getUnderlyingValue(), rhs.getUnderlyingValue(), &result))
+	// 		{
+	// 			throw std::overflow_error("division overflow");
+	// 		}
+	// 		return result;
+	// }
+	sint &operator++()
+	{
+		*this = *this + 1;
+		return *this;
+	}
+	sint operator++(int)
+	{
+		sint out(*this);
+		++(*this);
+		return out;
+	}
+
+	sint &operator--()
+	{
+		*this = *this - 1;
+		return *this;
+	}
+	sint operator--(int)
+	{
+		sint out(*this);
+		--(*this);
+		return out;
+	}
+	friend std::ostream &operator<<(std::ostream &os, const sint &s)
+	{
+		return os << s.getUnderlyingValue();
+	}
+};
+
+int main() {
+	// You are of course free to extend these tests!
+
+	// // just a small test
+	sint a = 1;
+	sint b(41);
+	sint c = a + b;
+	std::cout << c << '\n';
+
+	// // setup some values
+	sint max = std::numeric_limits<int>::max();
+	sint min = std::numeric_limits<int>::min();
+	sint result;
+
+	// // test operator+
+	// result = max + sint(10);
+	// std::cout << result << '\n';
+	// result = min + sint(-10);
+	// std::cout << result << '\n';
+
+	// // test operator-
+	// result = min - sint(10);
+	// std::cout << result << '\n';
+	// result = max - sint(-10);
+	// std::cout << result << '\n';
+
+	// // test operator*
+	// result = max * sint(2);
+	// std::cout << result << '\n';
+	// result = min * sint(2);
+	// std::cout << result << '\n';
+
+	// // test operator/
+	// result = sint(42) / sint(0);
+	// cout << result << '\n';
+	return 0;
+}
\ No newline at end of file
diff --git a/src/sheet05.cpp b/src/sheet05.cpp
new file mode 100644
index 0000000..e69de29