指针程序示例：
1.简单运算
//pointer.cpp
#include<iostream>
int main()
{
using namespace std;
int updates = 6;
int *p_updates;
p_updates = &updates;
//value
cout << "Value:updates = " << updates;
cout << ",*p_updates = " << *p_updates << endl;
//address
cout << "Address: &updates= " << &updates;
cout << ",p_update= " << p_updates;
cout << ",&p_updates= " << &p_updates;
//use pointer to change value:
*p_updates += 1;
cout << "Now updates= " << updates<<endl;
cout << *p_updates;
cin.get();
return 0;
}
注意：在*p_updates+=1时，本来想用*p_updates++替换，结果只是地址加1，该指针指向的地址改变了，原因出在运算符的优先运算级别。
应改为（*p_updates）++！！！
2.指针和new初级
//use_new.cpp
#include<iostream>
int main()
{
using namespace std;
int nights = 1001;
int* pt = new int; //allocate space for an int
*pt = 1001; //store a value here
cout << "nights value = "
<< nights << " : location = " << &nights << endl;
cout << "new int value = "
<< *pt << " : location = " << pt << endl;
double *pd = new double;
*pd = 1001.0;
cout << "double value = "
<< *pd << " : location = " << pd << endl;
cout << "location of pointer pd:" << &pd << endl;
cout <<"sizeof(pt)："<< sizeof(pt) << endl;
cout << "sizeof(*pt): " << sizeof(*pt) << endl;
cout << "sizeof(pt)：" << sizeof(pd) << endl;
cout << "sizeof(*pt): " << sizeof(*pd) << endl;
cin.get();
return 0;
}
注意：该程序运行结果指出，new分配的内存块通常与常规变量分配的内存块不同。变量nights和pd的值都存储在被称为栈（stack）的内存区域内，而new从被称为堆（heap）或自由存储区的内存区域分配内存。
3.new和数组
//arraynew.cpp
#include<iostream>
int main()
{
using namespace std;
double *p3 = new double[3]; //space for 3 doubles
p3[0] = 0.1; //treat p3 like an array name
p3[1] = 0.2;
p3[2] = 0.3;
cout << "p3[1] = " << p3[1] << endl;
p3 += 1; //increment the pointer
cout << "Now p3[0] = " << p3[0] << endl;
cout << " and the p3[1] = " << p3[1] << endl;
p3 = p3 - 1; //pointer back to the beginning
delete[]p3; //free the memory
cin.get();
return 0;
}
注意：指针最后必须指向原来的值，这样程序可以给delete[]提供正确的地址。
3.指针和字符串
//ptrstr.cpp--uaing pointers to strings
#include<iostream>
#include<cstring>
int main()
{
using namespace std;
char animal[20] = "bear";
const char *bird = "wren"; //bird holds address of string
char *ps;
cout << animal << " and " << bird << endl;
cout << "Enter a kind of animal:";
cin >> animal;
ps = animal;
cout << ps << endl;
cout << "Before using strcpy():\n";
cout << animal << " at " << (int*)animal << endl;
cout << ps << " at " << (int*)ps << endl;
}
警告：在将字符串读入程序时，应使用已经分配的内存地址。该地址可以是数组名，也可以是使用new初始化的指针。
一般来说，如果给cout提供一个指针，它将打印地址。但如果指针的类型为char*，则cout将显示指向的字符串。如果要显示的是字符串的地址，则必须将这种指针强制转换为另一种指针类型，如int*。
4.使用new创建动态结构
//newstrct.cpp--using new with a struct
#include<iostream>
struct inflatable
{
char name[20];
float volume;
double price;
};
int main()
{
using namespace std;
inflatable *ps = new inflatable; //allot memory for structure
cout << "Enter name of inflatable item: ";
cin.get(ps->name, 20);
cout << "Enter volume in cubic feet: ";
cin >> (*ps).volume;
cout << "Enter price: $";
cin >> ps->price;
cout << "Name: " << (*ps).name << endl;
cout << "Volume: " << ps->volume << endl;
cout << "Price: $: " << ps->price << endl;
delete ps;
cin.get();
cin.get();
return 0;
}
如果ps是指向结构的指针，则*ps就是被指向的值—结构本身。
5.一个使用new和delete的示例
//delete.cpp--using the delete operator
#pragma warning(disable:4996)
#include<iostream>
#include<string.h>
using namespace std;
char* getname(void); //function prototype
int main()
{
char* name;
name = getname();
cout << name << " at " << (int*)name << endl;
delete[]name;
name = getname(); //reuse freed memory
cout << name << " at " << (int*)name << endl;
delete[]name;
cin.get(); //只要有cin 多加一个cin.get
cin.get();
return 0;
}
char* getname()
{
char temp[80];
cout << "Enter last name: ";
cin>>temp;
char * pn = new char[strlen(temp) + 1];
strcpy(pn, temp);
return pn;
}
关于用[strlen(temp) + 1]
C-风格字符串具有一种特殊的性质：以空字符结尾（null character），空字符被写作\0。
6.类型组合
已经学习了数组、结构和指针，可以用各种方式组合它们。
//mixtypes.cpp--some type combinations
#include<iostream>
struct years
{
int year;
};
int main()
{
using std::cout;
years s0, s1, s2;
s0.year = 1998;
years *pa = &s1;
pa->year = 1999;
years tri[3];
tri[0].year = 2003;
cout << tri->year<<'\n';
const years *arp[3] = { &s0,&s1,&s2 };
cout << arp[1]->year << '\n';
const years **ppa = arp;
auto ppb = arp; //C++11 automatic type deduction
//or use const years **ppb=arp
cout << (*ppa)->year << '\n';
cout << (*(ppb + 1))->year << std::endl;
std::cin.get();
return 0;
}
7.比较数组、vector对象和array对象
//choice.cpp--array variations
#include<iostream>
#include<vector>
#include<array>
int main()
{
using namespace std;
//C, original C++
double a1[4] = { 1.2,2.4,3.6,4.8 };
//C++98 STL
vector<double>a2(4); //creat vector with 4 elements
//no simple way to initialize in C98
a2[0] = 1.0 / 3.0;
a2[1] = 1.0 / 5.0;
a2[2] = 1.0 / 7.0;
a2[3] = 1.0 / 9.0;
//C++11--create and initialize array object
array<double, 4>a3 = { 3.14,2.72 ,1.62,1.41 };
array<double, 4>a4;
a4 = a3; //valid for array object of same size
//use array notation
cout << "a1[2]: " << a1[2] << " at " << &a1[2] << endl;
cout << "a2[2]: " << a2[2] << " at " << &a2[2] << endl;
cout << "a3[2]: " << a3[2] << " at " << &a3[2] << endl;
cout << "a4[2]: " << a4[2] << " at " << &a4[2] << endl;
//misdeed
a1[-2] = 20.2;
cout << "a1[-2]: " << a1[-2] << " at " << &a1[-2] << endl;
cout << "a3[2]: " << a3[2] << " at " << &a3[2] << endl;
cout << "a4[2]: " << a4[2] << " at " << &a4[2] << endl;
cin.get();
return 0;
}
三种都可以用标准数组表示法来访问各个元素。从返回地址可知，array对象和数组存储在相同的内存区域（即栈）中，而vector对象存储在另一个区域（自由存储区域或堆）中，第三，注意到可以将一个array对象赋给另一个array对象；而对于数组，必须逐个元素复制数据。
a1[-2] = 20.2;
索引-2表示：
*(a1-2) = 20.2 ;
找到a1所指定的地方，向前移动两个double元素，并将20.2存储到目的地址中。