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Posted on 2010-04-16 10:31 小强摩羯座 阅读(237) 评论(0) 编辑 收藏 所属分类: C++ &VC
1
2
3
4#include<cstdio>
5#include<iostream>
6#include<cstdlib>
7#include<typeinfo>
8
9using namespace std;
10
11#define SIZE 8
12#define SEC (60*60UL)
13
14//1. test mem alignment
15#pragma pack(0)
16
17void fn1()
18   {
19 cout<<endl<<"next!"<<endl;
20
21 cout<<"---------------------"<<endl;
22
23 int a;
24 char b;
25 int c;
26 cout<<&a<<endl;
27 cout<<&b<<endl;
28 printf("0x%08x ", &b);
29 cout<<&c<<endl;
30
31// int ss[20] = "33424";
32 }
33//2.使用调用函数写入数据，而不是读出
34int * m_uiROIID = new int[SIZE];
35
36int* getROIID ()
37{
38 return m_uiROIID;
39}
40
41void prt()
42{
43 for (int i = 0;i < 3;i++)
44 scanf("%d", getROIID()+i);
45
46 for (int i = 0;i < SIZE;i++)
47  {
48 printf("%d ,", m_uiROIID[i]);
49 }
50}
51//3. a hash function
52long hashx(long x)
53{
54 long a = x | 0x0000FFFF;
55 long b = x >> 16;
56 return (a & ~b) | ( b & ~a);
57}
58
59//还不是很正确的
60void test()
61{
62 for (long i = 0; i < 5;i++)
63 printf(" %f\n", hashx(i) );
64}
65
66//4.引用指针用给参数分配空间
67void create(char *& p)
68{
69 p = new char;
70 p = "good idear";
71}
72void destroy(char *&p)
73{
74 delete p;
75}
76void testRefPoint()
77{
78 char* p = NULL;
79 if ( p == NULL) printf("%s", p);
80 else printf("not NULL \n");
81 create(p);
82 printf("%s", p);
83 if ( p == NULL) printf("NULL");
84 else printf("not NULL after create");
85
86 delete p;
87 printf("%s", p);
88 if ( p == NULL) printf("NULL");
89 else printf("not NULL after create");
90 printf("\n");
91}
92//5.指针类型决定加1操作的编移量
93void testPointer()
94{
95 int a[5] = {1,2,3,4,5};
96 int *ptr = (int*)(&a+1);
97 printf("%d %d" , *(a+1), *(ptr-1) );
98
99 printf("\n");
100}
101
102// 6.数据是传递指针，测试类型同5
103void foo(int [][3] );
104void main1()
105{
106 int a [3][3]= { { 1,2,3} , { 4,5,6},{7,8,9}};
107
108
109 printf("%d" , a[2][1]);
110 foo(a);
111 printf("%d" , a[2][1]);
112
113 printf("\n");
114}
115void foo( int b[][3])
116{
117 ++ b;
118 b[1][1] =9;
119}
120// 7.逗号表达式和指针使用
121void testP()
122{
123 int a, b,c, d;
124 a=3;
125 b=5;
126 c=a,b;
127 d=(a,b);
128 printf("c=%d" ,c);
129 printf("d=%d" ,d);
130
131 int arr[]={6,7,8,9,10};
132
133 int *ptr=arr;
134
135 *(ptr++)+=123;
136
137 printf("%d,%d",*ptr,*(++ptr));//它是从的计算的
138
139
140}
141//8。CPP的相等比较
142void testCStr()
143{
144 char str1[] = "abc";
145char str2[] = "abc";
146const char str3[] = "abc";
147const char str4[] = "abc";
148const char* str5 = "abc";
149const char* str6 = "abc";
150cout << ( str1==str2 ) << endl; // 输出什么？
151cout << ( str3==str4 ) << endl; // 输出什么？
152cout << ( str5==str6 ) << endl; // 输出什么？
153}
154
155//10.虚析构函数， 变量定义出现，typeid和type_info的使用
156class Base
157{
158 static const int Size = 9;
159 public:
160 Base()
161 {
162 cout<<"Base()'s ctor"<<endl;
163
164
165 }
166 virtual ~Base()=0;
167
168};
169 inline Base::~Base()
170 {
171 cout<<" Base's dtor"<<endl;
172 }
173
174class Derived:public Base
175{
176public:
177 Derived()
178 {
179 cout<<"int Derived ctor"<<endl;
180 }
181 ~Derived()
182 {
183 cout<<"int Derived dtor"<<endl;
184 }
185};
186
187//11.判断是c不是cpp程序, atexit 在main后调用函数
188void testCOrCpp()
189{
190 cout<<"is cpp"<<__cplusplus<<endl;
191// cout<<_STDC_<<endl;
192
193 atexit(fn1);
194}
195
196//12. test the class ctor and dtor
197//Base a;
198void testCtor()
199{
200 Base* pBase = new Derived;
201// Derived dObj;
202// pBase = &dObj;
203
204// delete pBase;
205
206 cout<<" ---------------before delete pBase--------"<<endl;
207
208 printf("******-----> %f", 5.);
209
210 printf("------> %d\n", 5);
211
212 char *p = "what";
213 p = "abc";
214 cout<<p<<endl;
215
216 if( typeid(*pBase) == typeid(Base) )
217 cout<<" typeid Base"<<endl;
218 else if( typeid( *pBase) == typeid(Derived))
219 cout<<" typeid Derived"<<endl;
220 else
221 cout<<" typeid NULL"<<endl;
222
223 const type_info& ti = typeid(*pBase);
224
225 cout<<"ti.name()= " << ti.name()<<endl;
226
227 cout<<"???????"<< typeid(*pBase).name()<<endl;
228
229}
230
231
232int main()
233{
234 int a[SIZE];
235
236 cout<<SEC<<endl;
237 // prt();
238// testCOrCpp();
239
240// testCStr();
241
242// testCtor();
243
244 testRefPoint(); /**//*
245 testPointer();
246
247 main1();
248 testP();
249
250 int *pA = new int;
251
252 delete pA;
253
254 *pA = 3;
255 */
256
257// test();
258}
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