diff --git a/src/NR.cpp b/src/NR.cpp
index d86584b..b32d64e 100644
--- a/src/NR.cpp
+++ b/src/NR.cpp
@@ -1,159 +1,130 @@
 #include "NR.h"
+
+#include <cassert>
 #include <iostream>
 
 int PGCD(int x, int y) {
-    if(x==0 || y==0)
-        return 1;
-    else if(x%y == 0)
-        return abs(y);
-    else
-        return PGCD(y, x%y);
+	if (x == 0 || y == 0)
+		return 1;
+	else if (x % y == 0)
+		return std::abs(y);
+	else
+		return PGCD(y, x % y);
 }
 
-NR::NR(int numerator, int denominator) {
-    NRset(numerator, denominator);
+NR::NR() : m_Numerator(0), m_Denominator(1) {}
+
+NR::NR(int entier) : m_Numerator(entier), m_Denominator(1) {}
+
+NR::NR(int numerator, int denominator) :
+	m_Numerator((denominator > 0) ? numerator : -numerator), m_Denominator(std::abs(denominator)) {
+	assert(denominator != 0);
 }
 
-void NR::NRset(int numerator, int denominator) {
-    if(denominator > 0)
-        m_Numerator = numerator;
-    else
-        m_Numerator = (-1)*numerator;
-    if(denominator == 0) {
-        std::cout<<"Essaie de créer une fraction avec un dénominateur = 0, impossible"<<std::endl;
-        exit(EXIT_FAILURE);
-    }
-    else
-        m_Denominator = abs(denominator);
+void NR::Reduce() {
+	int divisor = PGCD(m_Denominator, m_Numerator);
+	m_Denominator /= divisor;
+	m_Numerator /= divisor;
 }
 
-void NR::reduceNR() {
-    int divisor = PGCD(m_Denominator, m_Numerator);
-    m_Denominator /= divisor;
-    m_Numerator /= divisor;
+void NR::Invert() {
+	*this = NR(m_Denominator, m_Numerator);
 }
 
-void NR::invertNR() {
-    NRset(m_Denominator, m_Numerator);
+int NR::GetNumerator() const {
+	return m_Numerator;
 }
 
-int NR::NRgetNum() const {
-    return m_Numerator;
+int NR::GetDenominator() const {
+	return m_Denominator;
 }
 
-int NR::NRgetDen() const {
-    return m_Denominator;
+bool NR::operator==(const NR& opNR) const {
+	return (m_Numerator * opNR.GetDenominator() == m_Denominator * opNR.GetNumerator());
 }
 
-NR& NR::operator =(const NR& opNR) {
-    NRset(opNR.NRgetNum(),opNR.NRgetDen());
-    return *this;
+bool NR::operator<(const NR& opNR) const {
+	return (m_Numerator * opNR.GetDenominator() < m_Denominator * opNR.GetNumerator());
 }
 
-bool NR::operator ==(const NR& opNR) const {
-    return (m_Numerator * opNR.NRgetDen() == m_Denominator * opNR.NRgetNum());
+bool NR::operator>(const NR& opNR) const {
+	return (m_Numerator * opNR.GetDenominator() > m_Denominator * opNR.GetNumerator());
 }
 
-bool NR::operator <(const NR& opNR) const {
-    return (m_Numerator * opNR.NRgetDen() < m_Denominator * opNR.NRgetNum());
+bool NR::operator!=(const NR& opNR) const {
+	return !(*this == opNR);
 }
 
-bool NR::operator >(const NR& opNR) const {
-    return (m_Numerator * opNR.NRgetDen() > m_Denominator * opNR.NRgetNum());
+bool NR::operator<=(const NR& opNR) const {
+	return !(*this > opNR);
 }
 
-bool NR::operator !=(const NR& opNR) const {
-    return (not (*this == opNR));
+bool NR::operator>=(const NR& opNR) const {
+	return !(*this < opNR);
 }
 
-bool NR::operator <=(const NR& opNR) const {
-    return (not (*this > opNR));
+std::ostream& operator<<(std::ostream& os, const NR& opNR) {
+	os << opNR.GetNumerator() << "/" << opNR.GetDenominator();
+	return os;
 }
 
-bool NR::operator >=(const NR& opNR) const {
-    return (not (*this < opNR));
+std::istream& operator>>(std::istream& is, NR& opNR) {
+	char slash;
+	is >> opNR.m_Numerator >> slash >> opNR.m_Denominator;
+	opNR.Reduce();
+	return is;
 }
 
-std::ostream& operator <<(std::ostream& os, const NR& opNR) {
-    os<<opNR.NRgetNum()<<"/"<<opNR.NRgetDen();
-    return os;
+NR NR::operator+(const NR& opNR) const {
+	int num, den;
+	num = m_Numerator * opNR.GetDenominator();
+	den = m_Denominator * opNR.GetDenominator();
+	num += (opNR.GetNumerator() * m_Denominator);
+	NR result(num, den);
+	return result;
 }
 
-std::istream& operator >>(std::istream& is, NR& opNR) {
-    int num, den;
-    std::cout<<"Numerator: ";
-    is>>num;
-    std::cout<<"Denominator: ";
-    is>>den;
-    opNR.NRset(num, den);
-    return is;
+NR NR::operator-(const NR& opNR) const {
+	int num, den;
+	num = m_Numerator * opNR.GetDenominator();
+	den = m_Denominator * opNR.GetDenominator();
+	num -= (opNR.GetNumerator() * m_Denominator);
+	NR result(num, den);
+	return result;
 }
 
-NR NR::operator +(const NR& opNR) const {
-    int num, den;
-    num = m_Numerator * opNR.NRgetDen();
-    den = m_Denominator * opNR.NRgetDen();
-    num += (opNR.NRgetNum() *  m_Denominator);
-    NR result(num, den);
-    return result;
+NR NR::operator*(const NR& opNR) const {
+	int num, den;
+	num = m_Numerator * opNR.GetNumerator();
+	den = m_Denominator * opNR.GetDenominator();
+	NR result(num, den);
+	return result;
 }
 
-NR NR::operator -(const NR& opNR) const {
-    int num, den;
-    num = m_Numerator * opNR.NRgetDen();
-    den = m_Denominator * opNR.NRgetDen();
-    num -= (opNR.NRgetNum() *  m_Denominator);
-    NR result(num, den);
-    return result;
+NR NR::operator/(const NR& opNR) const {
+	int num, den;
+	num = m_Numerator * opNR.GetDenominator();
+	den = m_Denominator * opNR.GetNumerator();
+	NR result(num, den);
+	return result;
 }
 
-NR NR::operator *(const NR& opNR) const {
-    int num, den;
-    num = m_Numerator * opNR.NRgetNum();
-    den = m_Denominator * opNR.NRgetDen();
-    NR result(num, den);
-    return result;
+NR& NR::operator+=(const NR& opNR) {
+	*this = *this + opNR;
+	return *this;
 }
 
-NR NR::operator /(const NR& opNR) const {
-    int num, den;
-    num = m_Numerator * opNR.NRgetDen();
-    den = m_Denominator * opNR.NRgetNum();
-    NR result(num, den);
-    return result;
+NR& NR::operator-=(const NR& opNR) {
+	*this = *this - opNR;
+	return *this;
 }
 
-void NR::test() {
-    NR* frac = new NR;
-    NR frac2(3);
-    NR frac3(2,5);
-    int a, b;
-    std::cout<<"PGCD : entrez deux entiers"<<std::endl;
-    std::cin>>a>>b;
-    std::cout<<PGCD(a,b)<<std::endl;
-    std::cout<<"frac : entrez deux entiers"<<std::endl;
-    std::cin>>a>>b;
-    NR fractest(a, b);
-    std::cout<<fractest<<" + "<<frac3<<" = "<<std::endl;
-    std::cout<<">> "<<(fractest + frac3)<<std::endl;
-    std::cout<<">> "<<(fractest + frac3).NRgetNum()<<"/"<<(fractest + frac3).NRgetDen()<<std::endl;
-    fractest = fractest + frac3;
-    std::cout<<">> "<<fractest<<std::endl;
-    frac->NRset(2, 4);
-    NR anotherfrac;
-    std::cin>>anotherfrac;
-    std::cout<<"Compare "<<fractest<<" and "<<anotherfrac<<" : ==? "<<(fractest == anotherfrac)<<" <? "<<(fractest < anotherfrac)<<" >=? "<<(fractest >= anotherfrac)<< std::endl;
-    std::cout<<anotherfrac<<" - "<<*frac<<" = "<<anotherfrac - *frac<<std::endl;
-    std::cout<<anotherfrac<<" * "<<*frac<<" = "<<std::endl<<">> "<<anotherfrac * *frac<<std::endl;
-    fractest = anotherfrac * *frac;
-    std::cout<<">> "<<fractest<<std::endl;
-    fractest.reduceNR();
-    std::cout<<">> "<<fractest<<std::endl;
-    std::cout<<anotherfrac<<" / "<<frac2<<" = "<<anotherfrac / frac2<<std::endl;
-    NR numNR(2,4);
-    NR otherNR(3,1);
-    std::cout<<numNR<<" - "<<otherNR<<" = "<<std::endl;
-    NR subNR = numNR - otherNR;
-    std::cout<<">> "<<(numNR - otherNR)<<std::endl<<">> "<<subNR<<std::endl;
-    delete frac;
-}
\ No newline at end of file
+NR& NR::operator*=(const NR& opNR) {
+	*this = *this * opNR;
+	return *this;
+}
+
+NR& NR::operator/=(const NR& opNR) {
+	*this = *this / opNR;
+	return *this;
+}
diff --git a/src/NR.h b/src/NR.h
index 559ddda..2c67fa0 100644
--- a/src/NR.h
+++ b/src/NR.h
@@ -5,39 +5,41 @@
 class NR {
   private:
 	int m_Numerator;
-	int m_Denominator; //has to be > 0, sign is carried by the numerator
+	int m_Denominator;	// has to be > 0, sign is carried by the numerator
 
   public:
-	NR() : m_Numerator(0), m_Denominator(1) {}
+	NR();
+	NR(int entier);
+	NR(int numerator, int denominator);	 // check if denominator != 0
 
-	NR(int entier) : m_Numerator(entier), m_Denominator(1) {}
-	NR(int numerator, int denominator); //check if denominator != 0
-	void NRset(int numerator, int denominator); //same
+	int GetNumerator() const;
+	int GetDenominator() const;
 
-	void reduceNR(); //divide by PGCD, not automatically called yet
-	void invertNR();
+	bool operator==(const NR& opNR) const;
+	bool operator<(const NR& opNR) const;
+	bool operator>(const NR& opNR) const;
 
-	int NRgetNum() const;
-	int NRgetDen() const;
-	NR& operator =(const NR& opNR);
+	bool operator!=(const NR& opNR) const;
+	bool operator<=(const NR& opNR) const;
+	bool operator>=(const NR& opNR) const;
 
-	bool operator ==(const NR& opNR) const;
-	bool operator <(const NR& opNR) const;
-	bool operator >(const NR& opNR) const;
+	NR operator+(const NR& opNR) const;
+	NR operator-(const NR& opNR) const;
+	NR operator*(const NR& opNR) const;
+	NR operator/(const NR& opNR) const;
 
-	bool operator !=(const NR& opNR) const;
-	bool operator <=(const NR& opNR) const;
-	bool operator >=(const NR& opNR) const;
+	NR& operator+=(const NR& opNR);
+	NR& operator-=(const NR& opNR);
+	NR& operator*=(const NR& opNR);
+	NR& operator/=(const NR& opNR);
 
-	friend std::ostream& operator <<(std::ostream& os, const NR& opNR);
-	friend std::istream& operator >>(std::istream& os, NR& opNR);
+	void Invert();
 
-	NR operator +(const NR& opNR) const;
-	NR operator -(const NR& opNR) const;
-	NR operator *(const NR& opNR) const;
-	NR operator /(const NR& opNR) const;
+	friend std::ostream& operator<<(std::ostream& os, const NR& opNR);
+	friend std::istream& operator>>(std::istream& os, NR& opNR);
 
-	static void test();
+  private:
+	void Reduce();
 };
 
 int PGCD(int x, int y);