diff --git a/.gitignore b/.gitignore
index d5e4f15f8c02ac458b0019ffbb99d969fdc719db..5fb58aff55a75922b3006105626b794fd853899f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
-**/__pycache__
\ No newline at end of file
+**/__pycache__
+**/test.py
diff --git a/reed_solomon.py b/reed_solomon.py
index 3a36f11f6d564b042bf58571b0e37d737a2a0d33..1ae2c592576b3348a33ee01042f6c1744198e0e9 100644
--- a/reed_solomon.py
+++ b/reed_solomon.py
@@ -8,5 +8,10 @@ def lagrange_compute(l: list) -> polynome:
 	pass
 
 def check_nb_error(l: list, p: polynome) -> int:
-	pass
-
+	
+	nbr_error = 0
+	for _, item in enumerate(l):
+		if (item % p.prime_mod) != (p.evaluate(_) % p.prime_mod):
+			print(f"{item} != p.evaluate({_}) = {p.evaluate(_)}")
+			nbr_error += 1
+	return nbr_error