C++ Algorithm library by examples

• all_of, any_of, none_of
  • E.g. Check if all value in vector is positive.

vector<int> v{1, 2, 3};
bool allPositive = all_of(begin(v), end(v), [](int x) { return x > 0; });

• for_each, for_each_n
  • E.g. Iterate on value in vector, and can modify them.

vector<int> v{1, 2, 3};
// add 1 to every element
for_each(begin(v), end(v), [](int &x) { x++; });
for_each_n(begin(v), 3, [](int &x) { x++; });

• count, count_if
  • E.g. Count positive value in vector.

vector<int> v{1, 2, 3};

int target = 3;
int numOf3 = count(begin(v), end(v), target);
int numOfPositive = count_if(begin(v), end(v), [](int x) {return x > 0; });

• mismatch
  • E.g. Compare two vector, return first different value pair.

vector<int> v1{1, 2, 3};
vector<int> v2{1, 3, 3};
// Return first non-identical iterators
auto [it1, it2] = mismatch(begin(v1), end(v1), begin(v2));

auto [it1, it2] = mismatch(begin(v1), end(v1), begin(v2), [](int x, int y) { return x == y; });

• find, find_if, find_if_not
  • E.g. Find first non-positive value;

vector<int> v{1, 2, 3};
auto it = find_if_not(begin(v), end(v), [](int x) { return x > 0; });

• find_end
  • E.g.

• find_first_of

// Given a range and target array, find first element in range has element in target array
find_first_of(begin(v), end(v), )

• search

// Find if some seq is in other seq
const std::boyer_moore_searcher searcher(begin(sub), end(sub));
search(begin(target), end(target), searcher);