diff --git a/src/gcd.c b/src/gcd.c
index b083f1b..534f611 100644
--- a/src/gcd.c
+++ b/src/gcd.c
@@ -3,10 +3,16 @@
 const int n = 1000;
 
 unsigned int Euclidean_gcd_rec(unsigned int x, unsigned int y){
+  if(x == 0) return y;
+  return Euclidean_gcd_rec(y % x, x);
 }
 
 /*
 unsigned int Euclidean_gcd_itr(unsigned int x, unsigned int y){
+  while(x != 0){
+    unsigned int z = x;
+    x = y % x;
+    y = z;
 }
 
 unsigned int binary_gcd_rec(unsigned int x, unsigned int y){