diff --git a/practical_exercises/10_day_practice/day7/[]与()例题/example1.cpp b/practical_exercises/10_day_practice/day7/[]与()例题/example1.cpp
index 58a2827..89f5130 100644
--- a/practical_exercises/10_day_practice/day7/[]与()例题/example1.cpp
+++ b/practical_exercises/10_day_practice/day7/[]与()例题/example1.cpp
@@ -9,7 +9,7 @@ class X
 			return i; };
 	int operator[] (int i)
 	{ cout << "X::operator[" << i << "]" << endl; return i; };
-	int operator[] (char * cp)
+	int operator[] (const char * cp)
 	{ cout << "X::operator[" << cp << "]" << endl; return 0; };
 };
 int main (void)