面向对象程序设计-C++_课时19const_课时20不可修改的

 1 #include <iostream>
 2 using namespace std;
 3 
 4 void main()
 5 {
 6     const int class_size = 12;
 7     int finalGrade[class_size];
 8 
 9     int a = 12;
10     int arr[a];//error C2131: 表达式的计算结果不是常数
11 
12     int x;
13     std::cin >> x;
14     const int size = x;
15     double classAverage[size];//error C2131: 表达式的计算结果不是常数
16 
17     system("pause");
18 }

 1 #include <iostream>
 2 using namespace std;
 3 
 4 void main()
 5 {
 6     const char * s1 = "hello world";
 7     char s2[] = "hello world";
 8 
 9     std::cout << s1 << std::endl;
10     std::cout << s2 << std::endl;
11 
12     s1[0] = ‘a‘;//error C3892: “s1”: 不能给常量赋值
13     s2[0] = ‘a‘;
14 
15     std::cout << s1 << std::endl;
16     std::cout << s2 << std::endl;
17 
18     printf("s1=%p\n", &s1);
19     printf("s2=%p\n", &s2);
20 
21     system("pause");
22 }

 1 #include <iostream>
 2 using namespace std;
 3 
 4 class A
 5 {
 6     const int i;
 7 public:
 8     A() :i(0)
 9     {
10 
11     }
12     void f()
13     {
14         std::cout << "f()" << std::endl;
15     }
16     void f() const
17     {
18         std::cout << "f() const" << std::endl;
19     }
20 };
21 
22 void main()
23 {
24     const A a;
25     a.f();
26 
27     A a1;
28     a1.f();
29 
30     system("pause");
31 }