C++ Tutorial/File Stream/ostream iterator

Create ostream_iterator for writing int values to cout

<source lang="cpp">#include <iostream> using std::cout; using std::cin; using std::endl;

1. 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;

}</source>

Enter two integers: 1 2
The sum is: 3

transform algorithm with ostream_iterator

<source lang="cpp">#include <algorithm>

1. include <iostream>
2. 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;

}</source>

6 8 10 12 14

Use ostream_iterator

<source lang="cpp">#include <iostream>

1. 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;

}</source>

XY C++ Iterators are powerful.
187.23-102.7

Use ostream_iterator and copy to display collection content

<source lang="cpp">#include <iostream> using std::cout; using std::endl;

1. include <list> // list class-template definition
2. include <algorithm> // copy algorithm
3. 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;

}</source>

values contains: 3 1 4 2
otherValues contains: 2 6 4 8
values contains: 2 3 1 4 2 6 4 8