面积
代码示例：
1 #include <iostream>
2
3 using namespace std;
4
5 class circle {
6
7 public:
8 void set_r(int rr);
9 double c_circle();
10 double s_circle();
11
12 private:
13 int r;
14 };
15
16
17 void circle::set_r(int rr) {
18 r = rr;
19 }
20
21 double circle::c_circle() {
22 double c = 0;
23 c = r * 3.14 * 2 ;
24 cout << "c = " << c << endl;
25 return c;
26 }
27
28 double circle::s_circle() {
29 double s = 0 ;
30 s = r * r * 3.14;
31 cout << "s = " << s << endl;
32 return s;
33 }
34
35
36 int main(void) {
37 class circle temp;
38 temp.set_r(1);
39 temp.c_circle();
40 temp.s_circle();
41
42 system("pause");
43
44 return 0;
45 }
1 #include <iostream>
2
3 using namespace
