C++学习心得：求数组的元素个数

1
2
3
4
5
6
7
8
9
char c[] = "12345";
char d[10] = "678";

cout << "strlen c = " << strlen(c) << endl;
cout << "strlen d = " << strlen(d) << endl;


输出：5
      3

1
2
3
4
5
6
7
8
char c[] = "12345";
char d[10] = "678";

cout << "sizeof c = " << sizeof(c) / sizeof(c[0]) << endl;
cout << "sizeof d = " << sizeof(d) / sizeof(d[0]) << endl;

输出：6
      10

1
2
3
4
5
6
7
8
char c[] = "12345";
char d[10] = "678";

cout << "end-begin c = " << end(c) - begin(c) << endl;
cout << "end-begin d = " << end(d) - begin(d) << endl;

输出：6
     10

1
2
3
4
5
6
7
8
9
int a[] = { 1,2,3,4,5 };
int b[10] = { 6,7,8 };
	
cout << "sizeof a = " << sizeof(a) / sizeof(a[0]) << endl;
cout << "sizeof b = " << sizeof(b) / sizeof(b[0]) << endl;


输出：5
     10

1
2
3
4
5
6
7
8
9
int a[] = { 1,2,3,4,5 };
int b[10] = { 6,7,8 };
	
cout << "end-begin a = " << end(a) - begin(a) << endl;
cout << "end-begin b = " << end(b) - begin(b) << endl;


输出：5
     10

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
#define MAX 1000;    //通讯录的最大容量

struct Person    //联系人结构体
{
        string name;
        string telephone;
}

struct  AddressBook    //通讯录结构体
{
    Person personArray[MAX];
    int size ;

}



int main()
{
    AddressBook abs;    //实例化一个AddessBook结构变量
    abs.size = 0;

}

1
2
int a[] = {1, 2, 3};
length = sizeof(a) / sizeof(a[0]);