diff --git a/du3/program.c b/du3/program.c
index 92217e9..11720c4 100644
--- a/du3/program.c
+++ b/du3/program.c
@@ -100,6 +100,7 @@ int main()
             {
 			if(flag==-1 && mystack.values[mystack.size-1]==0)
 			{
+				printf("division by zero\n");
 				return 0;
 			}
                 float op_num=pop_stack(&mystack,input);