example_13_18.cpp

data+structures+using+c的源码

//STL Functions for_each and transform

#include <iostream>
#include <cctype>
#include <algorithm>
#include <iterator>
#include <vector>

using namespace std;

void doubleNum(int& num);

int main()
{
    char cList[5] = {'a', 'b', 'c', 'd', 'e'};        //Line 1

    vector<char> charList(cList, cList + 5);          //Line 2

    ostream_iterator<char> screen(cout, " ");         //Line 3

    cout<<"Line 4: charList: ";                       //Line 4
    copy(charList.begin(), charList.end(), screen);   //Line 5
    cout<<endl;                                       //Line 6

    transform(charList.begin(), charList.end(), 
              charList.begin(), toupper);		//Line 7

    cout<<"Line 8: charList after changing all lowercase" 
        <<" letters to \n        uppercase: ";        //Line 8
    copy(charList.begin(), charList.end(), screen);   //Line 9
    cout<<endl;                                       //Line 10


    int list[7] = {2, 8, 5, 1, 7, 11, 3};             //Line 11

    ostream_iterator<int> screenOut(cout, " ");       //Line 12

    cout<<"Line 13: list: ";                          //Line 13
    copy(list, list + 7, screenOut);                  //Line 14
    cout<<endl;                                       //Line 15

    cout<<"Line 16: The effect of the for_each "
        <<"function: ";                               //Line 16
    for_each(list, list + 7, doubleNum);              //Line 17
    cout<<endl;                                       //Line 18

    cout<<"Line 19: list after a call to the for_each "
        <<"function: ";                               //Line 19
    copy(list, list + 7, screenOut);                  //Line 20
    cout<<endl;                                       //Line 21
    
    return 0;
}

void doubleNum(int& num)
{
     num = 2 * num;
     cout<<num<<" ";
}