C++ Tutorial/File Stream/ostream iterator — различия между версиями
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Версия 14:21, 25 мая 2010
Содержание
Create ostream_iterator for writing int values to cout
#include <iostream>
using std::cout;
using std::cin;
using std::endl;
#include <iterator>
int main()
{
cout << "Enter two integers: ";
std::istream_iterator< int > inputInt( cin );
int number1 = *inputInt;
++inputInt;
int number2 = *inputInt;
std::ostream_iterator< int > outputInt( cout );
cout << "The sum is: ";
*outputInt = number1 + number2;
cout << endl;
return 0;
}Enter two integers: 1 2 The sum is: 3
transform algorithm with ostream_iterator
#include <algorithm>
#include <iostream>
#include <iterator>
using namespace std;
int sum(int val1, int val2) { return val2 + val1; }
int main()
{
int array1[5] = {0, 1, 2, 3, 4};
int array2[5] = {6, 7, 8, 9, 10};
ostream_iterator<int> out(cout, " ");
// Put sums of corresponding array1 and array2 elements into output stream:
transform(&array1[0], &array1[5], &array2[0], out, sum);
cout << endl;
return 0;
}6 8 10 12 14
Use ostream_iterator
#include <iostream>
#include <iterator>
using namespace std;
int main()
{
ostream_iterator<char> out_it(cout);
*out_it = "X";
out_it++;
*out_it = "Y";
out_it++;
*out_it = " ";
char str[] = "C++ Iterators are powerful.\n";
char *p = str;
while(*p) *out_it++ = *p++;
ostream_iterator<double> out_double_it(cout);
*out_double_it = 187.23;
out_double_it++;
*out_double_it = -102.7;
return 0;
}XY C++ Iterators are powerful. 187.23-102.7
Use ostream_iterator and copy to display collection content
#include <iostream>
using std::cout;
using std::endl;
#include <list> // list class-template definition
#include <algorithm> // copy algorithm
#include <iterator> // ostream_iterator
int main()
{
int array[ 4 ] = { 2, 6, 4, 8 };
std::list< int > values; // create list of ints
std::list< int > otherValues; // create list of ints
std::ostream_iterator< int > output( cout, " " );
// insert items in values
values.push_front( 1 );
values.push_front( 3 );
values.push_back( 4 );
values.push_back( 2 );
cout << "values contains: ";
std::copy( values.begin(), values.end(), output );
otherValues.insert( otherValues.begin(), array, array + 4 );
cout << "\n\notherValues contains: ";
std::copy( otherValues.begin(), otherValues.end(), output );
values.merge( otherValues );
cout << "\n\nvalues contains: ";
std::copy( values.begin(), values.end(), output );
cout << endl;
return 0;
}values contains: 3 1 4 2 otherValues contains: 2 6 4 8 values contains: 2 3 1 4 2 6 4 8
