指针巩固

 1 #include <iostream>
 2 using namespace std;
 3 int main()
 4 {
 5     int num = 0;
 6     int* p = &num;
 7     cout << p << "\t" << &num << endl;//0x6dfee8        0x6dfee8
 8     cout << *p << "\t" << num << endl;//0       0
 9     return 0;
10 }

 1 #include <iostream>
 2 using namespace std;
 3 int main()
 4 {
 5     int num = 0;
 6     int* p = &num;
 7     cout << p << "\t" << &num << endl;//0x6dfee8        0x6dfee8
 8     cout << *p << "\t" << num << endl;//0       0
 9 
10     char ch = 'd';
11     char* p_ch =&ch;
12     //char* 使p_ch会被当成字符串指针打印
13     cout << p_ch << "\t" << *p_ch << endl;//d       d
14     cout << (void*)p_ch << "\t" << *p_ch << endl;//0x6dfee3        d
15     return 0;
16 }

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 int main()
 4 {
 5     int a = 10;
 6     int &b = a;
 7     cout << b << a << endl;//1010
 8     //int &c=10;//报错，引用对象不可以赋值为一个常数。
 9     const int &d = 10;
10     cout << d << endl;//10
11     //加上const是常量引用，不加是变量引用
12     //引用相比于指针安全，所以推荐使用引用
13     return 0;
14 }

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 int main()
 4 {
 5     int num[4] = {1,2,5,4};
 6     int *p_a = num;
 7     int *p_b = &num[0];
 8     cout << p_a[0] << "---" << p_b[1] << endl;
 9     cout << *(++p_a) << "---" << *(p_b + 1) << endl;//*++num是不对的,不可以对数组名进行加减
10     
11     return 0;
12 }

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 int main()
 4 {
 5     int num[5];
 6     int *nums = new int[5];
 7     cout << sizeof(num) << '\t' << sizeof(nums) << endl;//20      4
 8     //一个是数组，一个是变量。
 9 
10     delete [] nums;
11     nums = nullptr;//指向空指针，否则就成为野指针。容易内存泄漏
12     int* ptr = new int;
13     delete ptr;
14     ptr = nullptr;
15     return 0;
16 }

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 int main()
 4 {
 5     int (*p)[3] = new int[3][3];
 6     p[1][1]=987;
 7     for(int i = 0;i < 3; i++){
 8         for(int j = 0;j< 3; j++){
 9             cout << p[i][j] <<"=="<< *(*(p+i)+j) << " || ";//两种输出方法
10         }
11         cout << endl;
12     }
13     return 0;
14 }