C++ Tutorial/STL Algorithms Non modifying sequence operations/copy backward
Содержание
copy_backward, merge, unique and reverse.
<source lang="cpp">#include <iostream>
- include <algorithm>
- include <vector>
using namespace std; int main() {
const int SIZE = 5; int a1[ SIZE ] = { 1, 3, 5, 7, 9 }; int a2[ SIZE ] = { 2, 4, 5, 7, 9 }; vector< int > v1( a1, a1 + SIZE ); vector< int > v2( a2, a2 + SIZE ); vector< int > results( v1.size() ); copy_backward( v1.begin(), v1.end(), results.end() ); vector< int > results2( v1.size() + v2.size() ); merge( v1.begin(), v1.end(), v2.begin(), v2.end(),results2.begin() ); vector< int >::iterator endLocation; endLocation = unique( results2.begin(), results2.end() ); reverse( v1.begin(), v1.end() ); cout << endl; return 0;
}</source>
Use copy_backward to copy value from vector to a list
<source lang="cpp">#include <algorithm>
- include <vector>
- include <list>
- include <iostream>
using namespace std; int main (){
list <int> l; for (int nCount = 0; nCount < 10; ++ nCount) l.push_back (nCount); list <int>::const_iterator li; for ( li = l.begin (); li != l.end (); ++ li ) cout << *li << " "; vector <int> v (l.size () * 2); copy_backward ( l.begin (), l.end (), v.end () ); vector <int>::const_iterator vi; for ( vi = v.begin (); vi != v.end (); ++ vi ) cout << *vi << " "; return 0;
}</source>
Use std::copy_backward to place elements in one vector into another vector in reverse order
<source lang="cpp">#include <iostream> using std::cout; using std::endl;
- include <algorithm>
- include <vector>
- include <iterator>
int main() {
int a1[ 5 ] = { 1, 3, 5, 7, 9 }; int a2[ 5 ] = { 2, 4, 5, 7, 9 }; std::vector< int > v1( a1, a1 + 5 ); std::vector< int > v2( a2, a2 + 5 ); std::ostream_iterator< int > output( cout, " " ); std::copy( v1.begin(), v1.end(), output ); // display vector output std::copy( v2.begin(), v2.end(), output ); // display vector output std::vector< int > results( v1.size() ); // place elements of v1 into results in reverse order std::copy_backward( v1.begin(), v1.end(), results.end() ); cout << "\n\nAfter copy_backward, results contains: "; std::copy( results.begin(), results.end(), output ); cout << endl; return 0;
}</source>
1 3 5 7 9 2 4 5 7 9 After copy_backward, results contains: 1 3 5 7 9
Use the copy_backward algorithms: Shift it right by 2 positions
<source lang="cpp">#include <iostream>
- include <cassert>
- include <algorithm>
- include <vector>
- include <string>
- include <iostream>
using namespace std; int main() {
string s("abcdefghihklmnopqrstuvwxyz"); vector<char> vector1(s.begin(), s.end()); copy_backward(vector1.begin(), vector1.end() - 2, vector1.end()); vector<char>::iterator pos; for (pos=vector1.begin(); pos!=vector1.end(); ++pos) { cout << *pos << " "; } return 0;
}</source>
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