STL_算法_替换(replacereplace_copyreplace_ifreplace_copy_if)

Posted 2022-12-13 寻找星空的孩子

C++ Primer 学习中。。。

 

简单记录下我的学习过程 (代码为主)

所有容器适用
replace(b,e,ov,nv)      //把oldvalue替换成newvalue
replace_if(b,e,p,v)     //把符合p条件的替换成v
replace_copy(b1,e1,b2,ov,nv)
replace_copy_if(b1,e1,b2,p,v)

/**------http://blog.csdn.net/u010579068------**/
#include<iostream>
#include<cstdio>
#include<string>
#include<vector>
#include<list>
#include<deque>
#include<algorithm>
using namespace std;

/*****************************************
//所有容器适用
replace(b,e,ov,nv)      //把oldvalue替换成newvalue
replace_if(b,e,p,v)     //把符合p条件的替换成v
replace_copy(b1,e1,b2,ov,nv)
replace_copy_if(b1,e1,b2,p,v)
*****************************************/
/**----------------------------------------------------------------------------------

----------------------------------------------------------------------------------**/
/*************************************************************************************
std::replace                     所有排序容器适用                           algorithm
--------------------------------------------------------------------------------------
template < class ForwardIterator, class T >
  void replace ( ForwardIterator first, ForwardIterator last,
                 const T& old_value, const T& new_value );

//eg：
template < class ForwardIterator, class T >
  void replace ( ForwardIterator first, ForwardIterator last,
                 const T& old_value, const T& new_value )

  for (; first != last; ++first)
    if (*first == old_value) *first=new_value;

*************************************************************************************/

/*************************************************************************************
std::replace_if                   所有排序容器适用                          algorithm
--------------------------------------------------------------------------------------
template < class ForwardIterator, class Predicate, class T >
  void replace_if ( ForwardIterator first, ForwardIterator last,
                    Predicate pred, const T& new_value );

//eg：
template < class ForwardIterator, class Predicate, class T >
  void replace_if ( ForwardIterator first, ForwardIterator last,
                    Predicate pred, const T& new_value )

  for (; first != last; ++first)
    if (pred(*first)) *first=new_value;

*************************************************************************************/

/*************************************************************************************
std::replace_copy                  所有排序容器适用                         algorithm
--------------------------------------------------------------------------------------
template < class InputIterator, class OutputIterator, class T >
  OutputIterator replace_copy ( InputIterator first, InputIterator last,
                                OutputIterator result,
                                const T& old_value, const T& new_value );

//eg：
template < class InputIterator, class OutputIterator, class T >
  OutputIterator replace_copy ( InputIterator first, InputIterator last,
                                OutputIterator result, const T& old_value, const T& new_value )

  for (; first != last; ++first, ++result)
    *result = (*first==old_value)? new_value: *first;
  return result;

*************************************************************************************/

/*************************************************************************************
std::replace_copy_if                  所有排序容器适用                     algorithm
--------------------------------------------------------------------------------------
template < class InputIterator, class OutputIterator, class Predicate, class T >
  OutputIterator replace_copy_if ( InputIterator first, InputIterator last,
                                   OutputIterator result, Predicate pred,
                                   const T& new_value );

//eg：
template < class InputIterator, class OutputIterator, class Predicate, class T >
  OutputIterator replace_copy_if ( InputIterator first, InputIterator last,
                                   OutputIterator result, Predicate pred,
                                   const T& new_value )

  for (; first != last; ++first, ++result)
    *result = (pred(*first))? new_value: *first;
  return result;

*************************************************************************************/

int main()

    int myints[] =  10, 20, 30, 30, 20, 10, 10, 20 ;
    vector<int> myvector (myints, myints+8);            // 10 20 30 30 20 10 10 20
//replace(b,e,ov,nv)
    replace (myvector.begin(), myvector.end(), 20, 99); // 10 99 30 30 99 10 10 99

    cout << "myvector contains:";
    for (vector<int>::iterator it=myvector.begin(); it!=myvector.end(); ++it)
        cout << " " << *it;

    cout << endl;
    /**--------------------------------------------------------------------------------**/

    myvector.clear();
    vector<int>::iterator it;

    // set some values:
    for (int i=1; i<10; i++) myvector.push_back(i);          // 1 2 3 4 5 6 7 8 9

    replace_if (myvector.begin(), myvector.end(), bind2nd(modulus<int>(),2), 0); // 0 2 0 4 0 6 0 8 0

    cout << "myvector contains:";
    for (it=myvector.begin(); it!=myvector.end(); ++it)
        cout << " " << *it;

    cout << endl;
    /**--------------------------------------------------------------------------------**/

//    int myints[] =  10, 20, 30, 30, 20, 10, 10, 20 ;

    list<int> mylist (8);
    replace_copy (myints, myints+8, mylist.begin(), 20, 66);

    cout << "mylist  contains: ";
    for (list<int>::iterator it=mylist.begin(); it!=mylist.end(); ++it)
        cout << " " << *it;

    cout << endl;
    /**--------------------------------------------------------------------------------**/

    deque<int> first,second;
    deque<int>::iterator id;

    // set some values:
    for (int i=1; i<10; i++) first.push_back(i);          // 1 2 3 4 5 6 7 8 9

    second.resize(first.size());   // allocate space
    replace_copy_if (first.begin(), first.end(), second.begin(), not1(bind2nd(modulus<int>(),2)), 0);
    // 1 0 3 0 5 0 7 0 9

    cout << "second  contains: ";
    for (id=second.begin(); id!=second.end(); ++id)
        cout << " " << *id;

    cout << endl;


    return 0;