1 /* strcpy函数实现 拷贝字符串 */
2 char* Strcpy(char* dst, char* src)
3 {
4 assert(dst != NULL && src != NULL); // 断言 dst和src不能为NULL
5
6 char* dst_address = dst; // 保存目的地址
7
8 while((*(dst++) = *(src++)) != '\0')
9 {
10 /* do nothing */
11 }
12
13 return dst_address; // 返回目的地址 允许链式表达式
14 }
15
16 /* strncpy函数实现*/
17
18 char* Strncpy(char* dst, const char* src, size_t num)
19 {
20 assert(dst != NULL && src != NULL); // 断言 dst和src不能为NULL
21
22 char* dst_address = dst;
23
24 size_t i = 0; // 控制复制的个数
25 while(i++ < num && (*dst++ = *src++) != '\0')
26 {
27 /* do nothing */
28 }
29
30 if(*dst != '\0') // 字符必须以'\0'结尾
31 {
32 *dst = '\0';
33 }
34
35 return dst_address;
36 }
37
38 size_t Strlen(const char *str)
39 {
40 assert(str != NULL);
41
42 int count = 0;
43
44 while(*str++ != '\0')
45 {
46 ++count;
47 }
48
49 return count;
50 }
51
52 void* Memcpy( void *dest, const void *src, size_t count )
53 {
54 assert(dest != NULL && src != NULL);
55
56 char* _dest = (char*)dest;
57 char* _src = (char*)src;
58
59 while (count--)
60 {
61 *_dest++ = *_src++;
62 }
63
64 return dest;
65 }
66
67 void * Memmove ( void * destination, const void * source, size_t num )
68 {
69 char* _dst = NULL;
70 char* _src = NULL;
71
72 if(destination <= source)
73 {
74 _dst = destination;
75 _src = source;
76
77 while (num--)
78 {
79 *_dst++ = *_src++;
80 }
81 }
82 else
83 {
84 _dst = destination;
85 _src = source;
86
87 _dst += num;
88 _src += num;
89
90 while (num--)
91 {
92 *--_dst = *--_src;
93 }
94 }
95 }
1 int FibonacciSequence(unsigned int n)
2 {
3 if(1 == n || 0 == n)
4 {
5 return n;
6 }
7 else
8 {
9 return FibonacciSequence(n-1)+FibonacciSequence(n-2);
10 }
11 }
1 int BinSearch(int* arr, int left, int right, int key)
2 {
3 if(!arr)
4 {
5 return -1;
6 }
7
8 while (left <= right)
9 {
10 int mid = left + ((right - left) >> 1);
11
12 if(arr[mid] < key)
13 {
14 left = mid + 1;
15 }
16 else if(arr[mid] > key)
17 {
18 right = mid - 1;
19 }
20 else
21 {
22 return mid;
23 }
24 }
25 return -1;
26 }
1 // 插入排序
2 void InsertionSort(int* arr, int len)
3 {
4 for(int j = 1; j < len; ++j)
5 {
6 int i = j - 1;
7 int key = arr[j];
8
9 while(i >= 0 && a[i] > key)
10 {
11 a[i+1] = a[i];
12 --i;
13 }
14 arr[i+1] = key;
15 }
16 }
1 int Partition(vector<int>& vec, int low, int up)
2 {
3 int pivot = vec[up];
4 int i = low - 1;
5
6 for(int j = low; j < up; ++j)
7 {
8 if(vec[i] < pivot)
9 {
10 ++i;
11 std::swap(vec[i], vec[j]);
12 }
13 }
14 std::swap(vec[i+1], vec[up]);
15
16 return i+1;
17 }
18
19 void QuickSort(vector<int>& vec, int low, int up)
20 {
21 if(low < up)
22 {
23 int mid = Partition(vec, low, up);
24
25 QuickSort(vec, low, mid - 1);
26 QuickSort(vec, mid + 1, up);
27 }
28 }
29
30 void Sort(vector<int>& vec)
31 {
32 QuickSort(vec, 0, vec.size() - 1);
33 }
template <typename T>
int BinSearch(std::vector<T>& array, T key)
{
int left = 0;
int right = array.size();
while (left < right)
{
int mid = (left + right) >> 1; // 中点
if (array[mid] < key)
{
left = mid;
}
else if (key < array[mid])
{
right = mid;
}
else
{
return mid;
}
}
return -1; // 查找失败
}
