C++ 不用临时变量交换两个变量的值——函数对象

雨点打透心脏的1/2处 2022-08-02 11:58 226阅读 0赞

1.  // 不使用中间临时变量，交换两对象的值 ，废话少说，直接上代码
2.  // Virtual.cpp : 定义控制台应用程序的入口点。
3.  
4.  \#include "stdafx.h"
5.  \#include <iostream>
6.  \#include <memory>
7.  \#include <algorithm>
8.  \#include <set>
9.  \#include <vector>
10. \#include <map>
11. \#include <string>
12. \#include <cstdlib>
13. **using****namespace** std; 
14. // 通过函数对象来实现插入排序
15. // 不用临时变量交换两个变量的值
16. // 方法1
17. **template** <**typename** T> 
18. **void** swap1(T& a, T& b) 
19. \{ 
20.  a ^= b; 
21.  b ^= a; 
22.  a ^= b; 
23. \} 
24. // 方法2
25. **template** <**typename** T> 
26. **void** swap2(T& a, T& b) 
27. \{ 
28.  a = a + b; 
29.  b = a - b; 
30.  a = a - b; 
31. \} 
32. 
33. /\*实现<的函数对象\*/
34. **template** <**typename** T> 
35. **class** LessThan 
36. \{ 
37. **public**: 
38. **bool** operator()(**const** T& left, **const** T& right) 
39.  \{ 
40. **return** left < right; 
41.  \} 
42. \}; 
43. /\*实现>的函数对象\*/
44. **template** <**typename** T> 
45. **class** GreaterThan 
46. \{ 
47. **public**: 
48. **bool** operator()(**const** T& left, **const** T& right) 
49.  \{ 
50. **return** left > right; 
51.  \} 
52. \}; 
53. /\*插入排序\*/
54. **template** <**typename** T, **typename** Compare> 
55. **void** insertSort(vector<T>& v, Compare cmp) 
56. \{ 
57. **int** size = v.size(); 
58. **for** (**int** i=1; i<size; i++) 
59.  \{ 
60. **int** temp = v\[i\]; 
61. **while**(i>0 && cmp(temp, v\[i-1\])) 
62.  \{ 
63.  v\[i\] = v\[i-1\]; 
64.  i--; 
65.  \} 
66.  v\[i\] = temp; 
67.  \} 
68. \} 
69. **int** main() 
70. \{ 
71.  vector<**int**> vec; 
72. **for** (**int** i=0; i<10; ++i) 
73.  \{ 
74.  vec.push\_back(rand()%100); 
75.  \} 
76.  printf("排序前:/n"); 
77.  copy(vec.begin(), vec.end(), ostream\_iterator<**int**>(cout, " ")); 
78. 
79.  printf("/n升序排列为:/n"); 
80.  LessThan<**int**> less; 
81.  insertSort(vec, less); 
82.  copy(vec.begin(), vec.end(), ostream\_iterator<**int**>(cout, " ")); 
83.  printf("/n降序排列为:/n"); 
84.  GreaterThan<**int**> great; 
85.  insertSort(vec, great); 
86.  copy(vec.begin(), vec.end(), ostream\_iterator<**int**>(cout, " ")); 
87.  printf("/n"); 
88. **int** a = 3; 
89. **int** b = 2; 
90.  printf("交换前a=%d b=%d/n", a, b); 
91.  swap1(a, b); 
92.  printf("交换后a=%d b=%d/n", a, b); 
93.  a = 5; 
94.  b = 6; 
95.  printf("交换前a=%d b=%d/n", a, b); 
96.  swap2(a, b); 
97.  printf("交换后a=%d b=%d/n", a, b); 
98. \}