1、指针的定义和使用

#include <iostream>
using namespace std;



int main() {

	int a = 10;
	int* p;
	p = &a;
	cout << "a的地址为：" << &a << endl;
	cout << "a的地址为：" << p << endl;

	*p = 1000;
	cout << "a = " << a << endl;
	cout << "*p = " << *p << endl;
	
	system("pause");
	return 0;
}

 

---

2、指针所占内存空间

#include <iostream>
using namespace std;



int main() {

	int a = 10;
	int* p = &a;

	//在32位操作系统下，指针是占4个字节空间大小，不管是什么数据类型
	//在64位操作系统下，指针是占8个字节空间大小，不管是什么数据类型
	cout << "指针占内存的大小:" << sizeof(int *) << endl;
	cout << "指针占内存的大小:" << sizeof(p) << endl;
	cout << "指针占内存的大小:" << sizeof(char *) << endl;
	cout << "指针占内存的大小:" << sizeof(float *) << endl;
	cout << "指针占内存的大小:" << sizeof(double *) << endl;


	
	system("pause");
	return 0;
}

---

3、空指针和野指针 

#include <iostream>
using namespace std;



int main() {

	//空指针
	int* p = NULL;

	//野指针  尽量避免野指针
	int* p = (int*)0x1100;
	
	system("pause");
	return 0;
}

---

4、const修饰指针

#include <iostream>
using namespace std;

int main() {

	//1、const修饰指针  常量指针 
	//指针指向的值不可以改，指针的指向可以改
	int a = 10;
	int b = 10;

	const int* p = &a;
	//*p=20; 错误
	p = &b;//正确

	//2、const修饰常量 指针常量
	//指针的指向不可以改，指针指向的值可以改
	int* const p2 = &a;
	*p2 = 100;//正确
	//p2 = &b;错误

	//3、const修饰指针和常量
	//指针的指向和指针指向的值都不可以改
	const int* const p3 = &a;
	//*p3 = 100;错误
	//p3 = &b;错误
	
	system("pause");
	return 0;
}

---

5、指针和数组

#include <iostream>
using namespace std;

int main() {

	int arr[10] = { 1,2,3,4,5,6,7,8,9,10 };

	int* p = arr;
	cout <<"利用指针访问第一个元素："<< * p << endl;

	p++;
	cout << "利用指针访问第二个元素：" << *p << endl;

	int* p2 = arr;
	for (int i = 0; i < 10; i++)
	{
		cout << *(p2 + i) << endl;
	}
	
	system("pause");
	return 0;
}

---

 6、指针和函数

#include <iostream>
using namespace std;


void swap(int * p1 ,int * p2) {
	int temp = *p1;
	*p1 = *p2;
	*p2 = temp;
	}

int main() {

	int a = 10;
	int b = 20;
	swap(&a, &b);
	cout << "a = " << a << endl;
	cout << "b = " << b << endl;
	
	system("pause");
	return 0;
}

---

7、案例 

案例描述:封装一个函数，利用冒泡排序，实现对整型数组的升序排序例如数组: int arr[10] ={ 4,3,6,9,1,2,10,8,7,5} ;

#include <iostream>
using namespace std;

void bubbleSort(int * arr,int len) {
	for (int i = 0; i < len - 1; i++) {
		for (int j = 0; j < len - i - 1; j++) {
			if (arr[j] > arr[j + 1]) {
				int temp = arr[j];
				arr[j] = arr[j + 1];
				arr[j + 1] = temp;
			}
		}
	}
}

void printfArray(int* arr, int len) {
	for (int i = 0; i < len; i++) {
		cout << arr[i] << endl;
	}
}

int main() {

	int arr[10] = { 4,3,6,9,1,2,10,8,7,5 };
	int len = sizeof(arr) / sizeof(arr[0]);
	bubbleSort(arr,len);

	printfArray(arr, len);

	system("pause");
	return 0;
}