Thinking In C++. Volume 2: Practical Programming

Returns an iterator pointing to the first occurrence of the "smallest" value in the range (as explained below—there may be multiple occurrences of this value.) Returns last if the range is empty. The first version performs comparisons with operator<, and the value r returned is such that *e < *r is false for every element e in the range [first, r). The second version compares using binary_pred, and the value r returned is such that binary_pred (*e, *r) is false for every element e in the range [first, r).

ForwardIterator max_element(ForwardIterator first, ForwardIterator last); ForwardIterator max_element(ForwardIterator first, ForwardIterator last, BinaryPredicate binary_pred);

Returns an iterator pointing to the first occurrence of the largest value in the range. (There may be multiple occurrences of the largest value.) Returns last if the range is empty. The first version performs comparisons with operator<, and the value r returned is such that *r < *e is false for every element e in the range [first, r). The second version compares using binary_pred, and the value r returned is such that binary_pred (*r, *e) is false for every element e in the range [first, r).

void replace(ForwardIterator first, ForwardIterator last, const T& old_value, const T& new_value); void replace_if(ForwardIterator first, ForwardIterator last, Predicate pred, const T& new_value); OutputIterator replace_copy(InputIterator first, InputIterator last, OutputIterator result, const T& old_value, const T& new_value); OutputIterator replace_copy_if(InputIterator first, InputIterator last, OutputIterator result, Predicate pred, const T& new_value);

Each of the "replace" forms moves through the range [first, last), finding values that match a criterion and replacing them with new_value. Both replace( ) and replace_copy( ) simply look for old_value to replace; replace_if( ) and replace_copy_if( ) look for values that satisfy the predicate pred. The "copy" versions of the functions do not modify the original range but instead make a copy with the replacements into result (incrementing result after each assignment).

Example

To provide easy viewing of the results, this example manipulates vectors of int. Again, not every possible version of each algorithm is shown. (Some that should be obvious have been omitted.)

//: C06:SearchReplace.cpp

// The STL search and replace algorithms

#include

#include

#include

#include "PrintSequence.h"

using namespace std;

struct PlusOne {

  bool operator()(int i, int j) {

    return j == i + 1;

  }

};

class MulMoreThan {

  int value;

public:

  MulMoreThan(int val) : value(val) {}

  bool operator()(int v, int m) {

    return v * m > value;

  }

};

int main() {

  int a[] = { 1, 2, 3, 4, 5, 6, 6, 7, 7, 7,

    8, 8, 8, 8, 11, 11, 11, 11, 11 };

  const int asz = sizeof a / sizeof *a;

  vector v(a, a + asz);

  print(v.begin(), v.end(), "v", " ");

  vector::iterator it =

    find(v.begin(), v.end(), 4);

  cout << "find: " << *it << endl;

  it = find_if(v.begin(), v.end(),

    bind2nd(greater(), 8));

  cout << "find_if: " << *it << endl;

  it = adjacent_find(v.begin(), v.end());

  while(it != v.end()) {

    cout << "adjacent_find: " << *it

      << ", " << *(it + 1) << endl;

    it = adjacent_find(it + 1, v.end());

  }

  it = adjacent_find(v.begin(), v.end(),

    PlusOne());

  while(it != v.end()) {

    cout << "adjacent_find PlusOne: " << *it

      << ", " << *(it + 1) << endl;

    it = adjacent_find(it + 1, v.end(),

      PlusOne());

  }

  int b[] = { 8, 11 };

  const int bsz = sizeof b / sizeof *b;

  print(b, b + bsz, "b", " ");

  it = find_first_of(v.begin(), v.end(),

    b, b + bsz);

  print(it, it + bsz, "find_first_of", " ");

  it = find_first_of(v.begin(), v.end(),

    b, b + bsz, PlusOne());

  print(it,it + bsz,"find_first_of PlusOne"," ");

  it = search(v.begin(), v.end(), b, b + bsz);

  print(it, it + bsz, "search", " ");

  int c[] = { 5, 6, 7 };

  const int csz = sizeof c / sizeof *c;

  print(c, c + csz, "c", " ");

  it = search(v.begin(), v.end(),

    c, c + csz, PlusOne());

  print(it, it + csz,"search PlusOne", " ");

  int d[] = { 11, 11, 11 };

  const int dsz = sizeof d / sizeof *d;

  print(d, d + dsz, "d", " ");

  it = find_end(v.begin(), v.end(), d, d + dsz);

  print(it, v.end(),"find_end", " ");

  int e[] = { 9, 9 };

  print(e, e + 2, "e", " ");

  it = find_end(v.begin(), v.end(),

    e, e + 2, PlusOne());

  print(it, v.end(),"find_end PlusOne"," ");

  it = search_n(v.begin(), v.end(), 3, 7);

  print(it, it + 3, "search_n 3, 7", " ");

  it = search_n(v.begin(), v.end(),

    6, 15, MulMoreThan(100));

  print(it, it + 6,

    "search_n 6, 15, MulMoreThan(100)", " ");

  cout << "min_element: " <<

    *min_element(v.begin(), v.end()) << endl;

  cout << "max_element: " <<

    *max_element(v.begin(), v.end()) << endl;

  vector v2;

  replace_copy(v.begin(), v.end(),

    back_inserter(v2), 8, 47);

  print(v2.begin(), v2.end(), "replace_copy 8 -> 47", " ");

  replace_if(v.begin(), v.end(),