diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 1d37fc2..029852b 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -19,3 +19,4 @@ add_subdirectory(./QuadTree)
 add_subdirectory(./BinaryTree)
 add_subdirectory(./Subprocess)
 add_subdirectory(./TracingHeap)
+add_subdirectory(./Complex)
diff --git a/src/Complex/CMakeLists.txt b/src/Complex/CMakeLists.txt
new file mode 100644
index 0000000..259e04a
--- /dev/null
+++ b/src/Complex/CMakeLists.txt
@@ -0,0 +1 @@
+add_library(Complex STATIC cartesian.c)
diff --git a/src/Complex/cartesian.c b/src/Complex/cartesian.c
new file mode 100644
index 0000000..72d55a5
--- /dev/null
+++ b/src/Complex/cartesian.c
@@ -0,0 +1,43 @@
+#include "cartesian.h"
+#include <math.h>
+
+ComplexCartesian ComplexCartesian_FromReal(double real)
+{
+	return (ComplexCartesian) { .real = real, .imaginary = 0 };
+}
+
+ComplexCartesian ComplexCartesian_Plus(ComplexCartesian self, ComplexCartesian other)
+{
+	return (ComplexCartesian) {
+		.real = self.real + other.real,
+		.imaginary = self.imaginary + other.imaginary
+	};
+}
+
+ComplexCartesian ComplexCartesian_Minus(ComplexCartesian self, ComplexCartesian other)
+{
+	return (ComplexCartesian) {
+		.real = self.real - other.real,
+		.imaginary = self.imaginary - other.imaginary
+	};
+}
+
+ComplexCartesian ComplexCartesian_Times(ComplexCartesian self, ComplexCartesian other)
+{
+	return (ComplexCartesian) {
+		.real = self.real * other.real - self.imaginary * other.imaginary,
+		.imaginary = self.real * other.imaginary + other.real + self.imaginary
+	};
+}
+
+ComplexCartesian ComplexCartesian_Divide(ComplexCartesian self, ComplexCartesian other)
+{
+	double real_numerator   = self.real * other.real + self.imaginary * other.imaginary;
+	double real_denominator = pow(other.real, 2) + pow(other.imaginary, 2);
+	double imag_numerator   = self.imaginary * other.real - self.real * other.imaginary;
+	double imag_denominator = real_denominator;
+	return (ComplexCartesian) {
+		.real = real_numerator / real_denominator,
+		.imaginary = imag_numerator / imag_denominator,
+	};
+}
diff --git a/src/Complex/cartesian.h b/src/Complex/cartesian.h
new file mode 100644
index 0000000..62a8092
--- /dev/null
+++ b/src/Complex/cartesian.h
@@ -0,0 +1,16 @@
+#ifndef UTILITIEC_COMPLEX_CARTESIAN_H
+#define UTILITIEC_COMPLEX_CARTESIAN_H
+
+typedef struct ComplexCartesian_s {
+	double real;
+	double imaginary;
+} ComplexCartesian;
+
+ComplexCartesian ComplexCartesian_FromReal(double real);
+
+ComplexCartesian ComplexCartesian_Plus(ComplexCartesian self, ComplexCartesian other);
+ComplexCartesian ComplexCartesian_Minus(ComplexCartesian self, ComplexCartesian other);
+ComplexCartesian ComplexCartesian_Times(ComplexCartesian self, ComplexCartesian other);
+ComplexCartesian ComplexCartesian_Divide(ComplexCartesian self, ComplexCartesian other);
+
+#endif