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diff --git a/fuzzylite/src/term/ZShape.cpp b/fuzzylite/src/term/ZShape.cpp
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+++ b/fuzzylite/src/term/ZShape.cpp
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+/*
+ fuzzylite (R), a fuzzy logic control library in C++.
+ Copyright (C) 2010-2017 FuzzyLite Limited. All rights reserved.
+ Author: Juan Rada-Vilela, Ph.D. <jcrada@fuzzylite.com>
+
+ This file is part of fuzzylite.
+
+ fuzzylite is free software: you can redistribute it and/or modify it under
+ the terms of the FuzzyLite License included with the software.
+
+ You should have received a copy of the FuzzyLite License along with
+ fuzzylite. If not, see <http://www.fuzzylite.com/license/>.
+
+ fuzzylite is a registered trademark of FuzzyLite Limited.
+ */
+
+#include "fl/term/ZShape.h"
+
+namespace fl {
+
+    ZShape::ZShape(const std::string& name, scalar start, scalar end, scalar height)
+    : Term(name, height), _start(start), _end(end) { }
+
+    ZShape::~ZShape() { }
+
+    std::string ZShape::className() const {
+        return "ZShape";
+    }
+
+    Complexity ZShape::complexity() const {
+        return Complexity().comparison(1 + 3).arithmetic(3 + 4).function(1);
+    }
+
+    scalar ZShape::membership(scalar x) const {
+        if (Op::isNaN(x)) return fl::nan;
+
+        if (Op::isLE(x, _start))
+            return Term::_height * 1.0;
+
+        if (Op::isLE(x, 0.5 * (_start + _end)))
+            return Term::_height * (1.0 - 2.0 * std::pow((x - _start) / (_end - _start), 2));
+
+        if (Op::isLt(x, _end))
+            return Term::_height * (2.0 * std::pow((x - _end) / (_end - _start), 2));
+
+        return Term::_height * 0.0;
+    }
+
+    scalar ZShape::tsukamoto(scalar activationDegree, scalar minimum, scalar maximum) const {
+        FL_IUNUSED(minimum);
+        FL_IUNUSED(maximum);
+
+        scalar w = activationDegree;
+        scalar z = fl::nan;
+
+        scalar difference = _end - _start;
+        scalar a = _start + std::sqrt(-0.5 * (w - 1.0) * difference * difference);
+        scalar b = _end + std::sqrt(0.5 * w * difference * difference);
+        if (std::abs(w - membership(a)) < std::abs(w - membership(b))) {
+            z = a;
+        } else {
+            z = b;
+        }
+        return z;
+    }
+
+    bool ZShape::isMonotonic() const {
+        return true;
+    }
+
+    std::string ZShape::parameters() const {
+        return Op::join(2, " ", _start, _end) +
+                (not Op::isEq(getHeight(), 1.0) ? " " + Op::str(getHeight()) : "");
+    }
+
+    void ZShape::configure(const std::string& parameters) {
+        if (parameters.empty()) return;
+        std::vector<std::string> values = Op::split(parameters, " ");
+        std::size_t required = 2;
+        if (values.size() < required) {
+            std::ostringstream ex;
+            ex << "[configuration error] term <" << className() << ">"
+                    << " requires <" << required << "> parameters";
+            throw Exception(ex.str(), FL_AT);
+        }
+        setStart(Op::toScalar(values.at(0)));
+        setEnd(Op::toScalar(values.at(1)));
+        if (values.size() > required)
+            setHeight(Op::toScalar(values.at(required)));
+    }
+
+    void ZShape::setStart(scalar start) {
+        this->_start = start;
+    }
+
+    scalar ZShape::getStart() const {
+        return this->_start;
+    }
+
+    void ZShape::setEnd(scalar end) {
+        this->_end = end;
+    }
+
+    scalar ZShape::getEnd() const {
+        return this->_end;
+    }
+
+    ZShape* ZShape::clone() const {
+        return new ZShape(*this);
+    }
+
+    Term* ZShape::constructor() {
+        return new ZShape;
+    }
+
+}