diff --git a/task1/task1.c b/task1/task1.c
index 88ba161..9c8f208 100644
--- a/task1/task1.c
+++ b/task1/task1.c
@@ -65,8 +65,12 @@ int main(int argc, char* argv[]) {
 			pos = strstr(pos, "777");
 		}
 		FILE* output_file = fopen(argv[2], "w");
-		fwrite(input_file -> contents, sizeof(char), input_file -> size_of_file, output_file);
-		fclose(output_file);
+		if (output_file == NULL) {
+			fprintf(stderr, "Error opening output file");
+		} else {
+			fwrite(input_file -> contents, sizeof(char), input_file -> size_of_file, output_file);
+			fclose(output_file);
+		}
 		close_file(input_file);
 		return 0;
 	}