4.8

如果给cout提供一个字符的地址，则他将从该字符开始打印，直到遇到空字符为止。

 1 #include<iostream>
 2 #include<cstring>
 3 int main()
 4 {
 5     using namespace std;
 6     char animal[20]="bear";
 7     const char*bird="wren";
 8     char *ps;
 9 
10     cout<<animal<<" and "<<bird<<endl;
11 
12     cout<<"enter a kind of animal";
13     cin>>animal;
14 
15     ps=animal;
16     cout<<ps<<endl;
17 
18     cout<<"before using strcpy()"<<endl;
19     cout<<animal<<" at "<<(int*)animal<<endl;//地Ì?址¡¤
20     cout<<ps<<" at "<<(int*)ps<<endl;
21 
22     ps=new char[strlen(animal)+1];
23     strcpy(ps,animal);
24     
25     cout<<"after using strcpy()"<<endl;
26     cout<<animal<<" at "<<(int*)animal<<endl;
27     cout<<ps<<" at "<<(int*)ps<<endl;
28 
29     delete[] ps;
30     return 0;
31 }

应使用strcpy（）或strncpy（）而不是赋值运算符来将字符串赋给数组。

使用new创建动态结构

创建结构

inflatable *ps=new inflatable；

这将把足以存储inflatable结构的一块可用内存的地址赋给ps。

箭头运算符 ->

如果结构标识符是结构名，就用句点运算符。如果标识符是指针，就用箭头运算符。

 1 #include<iostream>
 2 struct inflatable
 3 {
 4     char name[20];
 5     float volume;
 6     double price;
 7 };
 8 
 9 int main()
10 {
11     using namespace std;
12     inflatable *ps=new inflatable;
13     cout<<"enter name of inflatable item";
14     cin.get(ps->name,20);
15     cout<<"enter volume in cubic feet";
16     cin>>(*ps).volume;
17     cout<<"enter price";
18     cin>>ps->price;
19     cout<<"name:"<<(*ps).name<<endl<<"volume:"<<ps->volume<<endl<<"price:"<<ps->price<<endl;
20     return 0;
21 }

一个new和delete的实例

 1 #include<iostream>
 2 #include<cstring>
 3 using namespace std;
 4 char *getname();
 5 int main()
 6 {
 7     char *name;
 8 
 9     name=getname();
10     cout<<name<<" at "<<(int*)name<<endl;
11     delete []name;
12     
13     name=getname();
14     cout<<name<<" at "<<(int*)name<<endl;
15     delete []name;
16 
17     return 0;
18 }
19 
20 char *getname()
21 {
22     char temp[80];
23     cout<<"enter last name";
24     cin>>temp;
25     char *pn=new char[strlen(temp)+1];
26     strcpy(pn,temp);
27     return pn;
28 }

将new和delete放在不同的函数中不是一个好方法，容易忘掉使用delete。