remove_if |
C++ Library |
template<class ForwardIterator, class Predicate> inline ForwardIterator remove_if(ForwardIterator first, ForwardIterator last, Predicate pred)
The remove_if algorithm removes all elements from the range (first, last) that cause the predicate to return true. It returns an iterator equal to last - N, where N = number of elements removed. The last N elements of the range have undefined values. The size of the container remains the same.
// disable warning C4786: symbol greater than 255 character, // okay to ignore #pragma warning(disable: 4786) #include <iostream> #include <vector> #include <algorithm> #include <functional> using namespace std; void main() { const int VECTOR_SIZE = 8 ; // Define a template class vector of integers typedef vector<int > IntVector ; //Define an iterator for template class vector of integer typedef IntVector::iterator IntVectorIt ; IntVector Numbers(VECTOR_SIZE) ; //vector containing numbers IntVectorIt start, end, it, last; start = Numbers.begin() ; // location of first // element of Numbers end = Numbers.end() ; // one past the location // last element of Numbers //Initialize vector Numbers Numbers[0] = 10 ; Numbers[1] = 20 ; Numbers[2] = 10 ; Numbers[3] = 15 ; Numbers[4] = 12 ; Numbers[5] = 7 ; Numbers[6] = 9 ; Numbers[7] = 10 ; cout << "Before calling remove_if" << endl ; // print content of Numbers cout << "Numbers { " ; for(it = start; it != end; it++) cout << *it << " " ; cout << " }\n" << endl ; // remove all elements from Numbers that <= 10 last = remove_if(start, end, bind2nd(less_equal<int>(), 10) ) ; cout << "After calling remove_if" << endl ; // print content of Numbers cout << "Numbers { " ; for(it = start; it != end; it++) cout << *it << " " ; cout << " }\n" << endl ; //print number of elements removed from Numbers cout << "Total number of elements removed from Numbers = " << end - last << endl ; //print only the valid elements of Number cout << "Valid elements of Numbers { " ; for(it = start; it != last; it++) cout << *it << " " ; cout << " }\n" << endl ; }
Before calling remove_if Numbers { 10 20 10 15 12 7 9 10 } After calling remove_if Numbers { 20 15 12 15 12 7 9 10 } Total number of elements removed from Numbers = 5 Valid elements of Numbers { 20 15 12 }