1、指针变量
#include <iostream>using namespace std;int main ()
{int var = 20; // 实际变量的声明int *ip; // 指针变量的声明ip = &var; // 在指针变量中存储 var 的地址cout << "Value of var variable: ";cout << var << endl;// 输出在指针变量中存储的地址cout << "Address stored in ip variable: ";cout << ip << endl;// 访问指针中地址的值cout << "Value of *ip variable: ";cout << *ip << endl;return 0;
}
2、指针函数
#include <iostream>
#include <ctime>using namespace std;// 在写函数时应习惯性的先声明函数,然后在定义函数
void getSeconds(unsigned long *par);int main ()
{unsigned long sec;getSeconds( &sec );// 输出实际值cout << "Number of seconds :" << sec << endl;return 0;
}void getSeconds(unsigned long *par)
{// 获取当前的秒数*par = time( NULL );return;
}
3、函数指针
#include <iostream>
#include <ctime>
#include <cstdlib>using namespace std;// 要生成和返回随机数的函数
int * getRandom( )
{static int r[10];// 设置种子srand( (unsigned)time( NULL ) );for (int i = 0; i < 10; ++i){r[i] = rand();cout << r[i] << endl;}return r;
}// 要调用上面定义函数的主函数
int main ()
{// 一个指向整数的指针int *p;p = getRandom();for ( int i = 0; i < 10; i++ ){cout << "*(p + " << i << ") : ";cout << *(p + i) << endl;}return 0;
}
4、类指针
#include <iostream>using namespace std;class Box
{public:// 构造函数定义Box(double l=2.0, double b=2.0, double h=2.0){cout <<"Constructor called." << endl;length = l;breadth = b;height = h;}double Volume(){return length * breadth * height;}private:double length; // Length of a boxdouble breadth; // Breadth of a boxdouble height; // Height of a box
};int main(void)
{Box Box1(3.3, 1.2, 1.5); // Declare box1Box Box2(8.5, 6.0, 2.0); // Declare box2Box *ptrBox; // Declare pointer to a class.// 保存第一个对象的地址ptrBox = &Box1;// 现在尝试使用成员访问运算符来访问成员cout << "Volume of Box1: " << ptrBox->Volume() << endl;// 保存第二个对象的地址ptrBox = &Box2;// 现在尝试使用成员访问运算符来访问成员cout << "Volume of Box2: " << ptrBox->Volume() << endl;return 0;
}