diff --git a/Projet/Propagatio.cc b/Projet/Propagatio.cc
index 0319979..44976fd 100644
--- a/Projet/Propagatio.cc
+++ b/Projet/Propagatio.cc
@@ -1,195 +1,195 @@
 // Propagatio.cc
 // Auteur : Quentin Berling
 // Version : 1.0
 #include <iostream>
 #include <iomanip>
 #include <vector>
 #include <algorithm>
 #include <string> 
 using namespace std;
 
 
 const string P1("P1 missing or incorrect");
 const string WRONG_NB_COL_LGN("Nb columns and/or nb lines incorrect");
 const string MATRIX_SQUARE("Matrix is not square");
 const string IRREGULAR_CONTENT("Matrix description with incorrect content");
 const string DISCONNECTED_GRAPH("Matrix corresponds to a disconnected graph");
 
 
 typedef vector<bool> Vector;
 typedef vector<Vector> Matrix;
 
 
 int check_bpm();
 Matrix make_adj(int n);
-void explore(int n, Matrix mat, Vector &visited, int l);
-void connect_ck(int n, Matrix mat);
-void visit_node_and(int n, Matrix &mat, Vector &visited,
+void explore(int n, const Matrix &mat, Vector &visited, int l);
+void connect_ck(int n, const Matrix &mat);
+void visit_node_and(int n, const Matrix &mat, Vector &visited,
 					vector<int> &to_visit_next, int node);
-void propagate(int n, Matrix mat);
-double degree_ck(int n, Matrix mat, int n0);
+void propagate(int n, const Matrix &mat);
+double degree_ck(int n, const Matrix &mat, int n0);
 
 
 int main() {
 	int n;
 	n=check_bpm();
 	Matrix matAdj(n, Vector(n));
 	matAdj=make_adj(n);
     
 	connect_ck(n, matAdj);
 	
 	propagate(n, matAdj);
 
 	double degree(0);
 	for (int i(0); i<n; i++) {
 		degree=degree+degree_ck(n, matAdj, i);
 	}
 	cout << setprecision(6) << fixed << degree/n << endl;
     
 	return 0;
 }
 
 
 int check_bpm() {
 	int n;
 	string header;
 // 	cout << "Header P1 ?" << endl;
 	cin >> header;
 	if (header != "P1") {
 	    cout << P1 << endl;
 		exit(0);
 	}
 	
 	int c,l;
 // 	cout << "Nombre de colonnes ?" << endl;
 	cin >> c;
 // 	cout << "Nombre de lignes ?" << endl;
 	cin >> l;
 	if (l == c) {
 		n=l;
 	}
 	else {
 		cout << MATRIX_SQUARE << endl;
 		exit(0);
 	}
 	if (n == 0) {
 		cout << WRONG_NB_COL_LGN << endl;
 		exit(0);
 	}
 	
 	return n;
 }
 
 
 Matrix make_adj(int n) {
 	Matrix mat(n, Vector(n));
 	for (int i(0); i < n; i++) {
 		char c;
 		int j(0);
 		cin >> c;
 		while (c != '\n') {
 			if (c == '0' || c == '1') {
 				mat[i][j]=int(c)-int('0');
 				j++;
 			} else if (! isspace(c)) {
 				cout << IRREGULAR_CONTENT << endl;
 				exit(0);
 			}
 			cin.get(c);
 		}
 		if (j != n) {
 			cout << WRONG_NB_COL_LGN << endl;
 			exit(0);
 		}
 		mat[i][i]=0;
 	}
 	for (int i(0); i < n; i++) {
 		for (int j(0); j < n; j++) {
 			if (mat[i][j] == 1) {
 				mat[j][i]=1;
 			}
 		}
 	}
 	
 	return mat;
 }
 
 
-void explore(int n, Matrix mat, Vector &visited, int l) {
+void explore(int n, const Matrix &mat, Vector &visited, int l) {
 	visited[l]=1;
 	for (int c(0); c < n; c++) {
 		if (visited[c] == 0 && mat[l][c] == 1) {
 			explore(n, mat, visited, c);
 		}
 	}
 }
 
 
-void connect_ck(int n, Matrix mat) {
+void connect_ck(int n, const Matrix &mat) {
 	Vector visited(n);
 	explore(n, mat, visited, 0);
 	if (find(visited.begin(), visited.end(), 0) != visited.end()) {
 		cout << DISCONNECTED_GRAPH << endl;
 		exit(0);
 	}
 }
 
 
-void visit_node_and(int n, Matrix &mat, Vector &visited,
+void visit_node_and(int n, const Matrix &mat, Vector &visited,
 					vector<int> &to_visit_next, int node) {
 	visited[node]=1;
 	for (int c(0); c < n; c++) {
 		if (visited[c] == 0 && mat[node][c] == 1) {
 			to_visit_next.push_back(c);
 		}
 	}
 }
 
 
-void propagate(int n, Matrix mat) {
+void propagate(int n, const Matrix &mat) {
 	Vector visited(n);
 	vector<int> to_visit({0}), to_visit_next;
 	string propagation;
 	do {
 		for (int node : to_visit) {
 			if (visited[node] != 1) {
 				propagation=propagation + to_string(node) + " ";
 				visit_node_and(n, mat, visited, to_visit_next, node);
 			}
 		}
 		
 		propagation.pop_back();
 		cout << propagation << endl;
 		propagation.clear();
 		
 		to_visit=to_visit_next;
 		to_visit_next.clear();
 		sort(to_visit.begin(), to_visit.end());
 	} while (find(visited.begin(), visited.end(), 0) < visited.end());
 }
 
 
-double degree_ck(int n, Matrix mat, int n0) {
+double degree_ck(int n, const Matrix &mat, int n0) {
 	Vector visited(n);
 	vector<int> to_visit({n0}), to_visit_next;
 	int i(0);
 	double deg(0);
 	do {
 		for (int node : to_visit) {
 			if (visited[node] != 1) {
 				deg=deg+i;
 				visit_node_and(n, mat, visited, to_visit_next, node);
 			}
 		}
 		
 		to_visit=to_visit_next;
 		to_visit_next.clear();
 		i++;
 	} while (find(visited.begin(), visited.end(), 0) < visited.end());
 	
 	if (n > 1) {
 		deg=deg/(n-1);
 	}
 		
 	return deg;
 }