# Use for_each with predicate : for_each « STL Algorithms Non modifying sequence operations « C++ Tutorial

```#include <iostream>
using std::cout;
using std::endl;

#include <algorithm>
#include <numeric>
#include <vector>
#include <iterator>

void outputSquare( int );

int main()
{
std::ostream_iterator< int > output( cout, " " );

int a2[ 10 ] = { 100, 2, 8, 1, 50, 3, 8, 8, 9, 10 };
std::vector< int > v2( a2, a2 + 10 ); // copy of a2
cout << "Vector v2 contains: ";
std::copy( v2.begin(), v2.end(), output );

// output square of every element in v
cout << "\n\nThe square of every integer in Vector v is:\n";
std::for_each( v2.begin(), v2.end(), outputSquare );

cout << endl;
return 0;
}
void outputSquare( int value )
{
cout << value * value << ' ';
}
```
```Vector v2 contains: 100 2 8 1 50 3 8 8 9 10

The square of every integer in Vector v is:
10000 4 64 1 2500 9 64 64 81 100```
 25.11.for_each 25.11.1. Use for_each with predicate 25.11.2. Use for_each function to add value for each element 25.11.3. Use for_each function to add first element to each element in the list 25.11.4. Use for_each function to print all elements in a vector 25.11.5. Call custom function in for_each 25.11.6. Use custom function and for_each to calculate mean value 25.11.7. Use for_each() algorithm to show elements in a vector and do the summation 25.11.8. Using for_each to Display the Contents of a Collection 25.11.9. The square of every integer in a vector