STL中的equal函数

STL中的equal函数：

template<class InputIterator1, class InputIterator2>
   bool equal(
      InputIterator1 _First1, 
      InputIterator1 _Last1, 
      InputIterator2 _First2
      );
template<class InputIterator1, class InputIterator2, class BinaryPredicate>
   bool equal(
      InputIterator1 _First1, 
      InputIterator1 _Last1, 
      InputIterator2 _First2, 
      BinaryPredicate _Comp
      );

View Code

 1 // alg_equal.cpp
 2 // compile with: /EHsc
 3 #include <vector>
 4 #include <algorithm>
 5 #include <iostream>
 6 
 7 // Return whether second element is twice the first
 8 bool twice ( int elem1, int elem2 )
 9 {
10    return elem1 * 2 == elem2;
11 }
12 
13 int main( )
14 {
15    using namespace std;
16    vector <int> v1, v2, v3;
17    vector <int>::iterator Iter1, Iter2, Iter3;
18 
19    int i;
20    for ( i = 0 ; i <= 5 ; i++ )
21    {
22       v1.push_back( 5 * i );
23    }
24 
25    int ii;
26    for ( ii = 0 ; ii <= 5 ; ii++ )
27    {
28       v2.push_back( 5 * ii );
29    }
30 
31    int iii;
32    for ( iii = 0 ; iii <= 5 ; iii++ )
33    {
34       v3.push_back( 10 * iii );
35    }
36    
37    cout << "v1 = ( " ;
38    for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
39       cout << *Iter1 << " ";
40    cout << ")" << endl;
41 
42    cout << "v2 = ( " ;
43    for ( Iter2 = v2.begin( ) ; Iter2 != v2.end( ) ; Iter2++ )
44       cout << *Iter2 << " ";
45    cout << ")" << endl;
46 
47    cout << "v3 = ( " ;
48    for ( Iter3 = v3.begin( ) ; Iter3 != v3.end( ) ; Iter3++ )
49       cout << *Iter3 << " ";
50    cout << ")" << endl;
51 
52    // Testing v1 and v2 for equality under identity
53    bool b;
54    b = equal( v1.begin( ), v1.end( ), v2.begin( ) );
55 
56    if ( b )
57       cout << "The vectors v1 and v2 are equal under equality."
58            << endl;
59    else
60       cout << "The vectors v1 and v2 are not equal under equality."
61            << endl;
62 
63    // Testing v1 and v3 for equality under identity
64    bool c;
65    c = equal( v1.begin( ), v1.end( ), v3.begin( ) );
66 
67    if ( c )
68       cout << "The vectors v1 and v3 are equal under equality."
69            << endl;
70    else
71       cout << "The vectors v1 and v3 are not equal under equality."
72            << endl;
73 
74    // Testing v1 and v3 for equality under twice
75    bool d;
76    d = equal( v1.begin( ), v1.end( ), v3.begin( ), twice );
77 
78    if ( d )
79       cout << "The vectors v1 and v3 are equal under twice."
80            << endl;
81    else
82       cout << "The vectors v1 and v3 are not equal under twice."
83            << endl;
84 }
85  
86 /*
87 Output
88   
89 v1 = ( 0 5 10 15 20 25 )
90 v2 = ( 0 5 10 15 20 25 )
91 v3 = ( 0 10 20 30 40 50 )
92 The vectors v1 and v2 are equal under equality.
93 The vectors v1 and v3 are not equal under equality.
94 The vectors v1 and v3 are equal under twice.
95  */

posted on 2012-06-10 15:06 cchun 阅读(2051) 评论(0) 编辑收藏举报