构造函数里加const

 1 #include <iostream>
 2 using namespace std;
 3 
 4 class MyString{
 5 private:
 6     char * p;
 7     int len;
 8 public:
 9     MyString(const char *s){
10         len = strlen(s);
11         p = new char[len+1];
12         strcpy(p,s);
13     }
14     /*
15     MyString(char *s){
16      len = strlen(s);
17         p = new char[len+1];
18         strcpy(p,s);
19     }
20      */
21 };
22 int main(){
23     MyString s1("aaa");
24     return 0;
25 }