Functions in the algorithm header file: remove() and remove

remove(first, last, value) function removes the value of [first, last) range，returns the tail iterator of the new value range

at the head The declaration in the file is as follows

template ForwardIt remove( ForwardIt first, ForwardIt last, const T& value );//first, last are all iterators，value is a value or object，returns the last iterator of the new value range

　The usage method is as follows

vector a = {11, 0, 2, 3, 10, 0, 0, 8, 0} ;cout <<"Original size : " <

remove_if() function

template ForwardIt remove_if( ForwardIt first, ForwardIt last, UnaryPredicate p ); //Remove all elements that meet specific criteria from the range [first, last) ， and return Iterator after the end of the new value range.

Use as follows

vector a = {11, 0, 2, 3 , 10, 0, 0, 8, 0};cout <<"Original size : " <// auto itend = remove_if(a.begin(), a.end(), bind2nd(greater( ),9));//Remove numbers greater than 9 auto itend = remove_if(a.begin(), a.end(), [](int i){return i>9;});/ / You can also use lambda expressions or write a bool type function and use the function name as the third parameter. cout <<"after REMOVE, size : " <

In addition,，in the header file，there are count() function and count_if() function usage and the above resemblance. find() and find_if()

count(first, last, value)

Where ，first and last are iterators or pointers& #xff0c;Represents the range [first, last)，value is a value or object. Returns the number of elements in [first, last) equal to value.

count_if(first, last, p)

Where ，first and last are iterators or pointers，representing the range [first , last)，p is a unary predicate，can be a function object，returns a bool type function name（that is, a function pointer），lambda expression. Return the number of elements that satisfy p condition

find(first, last, value)

Returns the iterator of the first element in the range [first, last) that is equal to value. If ， is not found, last is returned.

find_if(first, last, p)

Returns the iterator of the first element in the range [first, last) that satisfies the condition of p. If ， is not found, last is returned.

p is a unary predicate ， can be a function object， returns a bool type function name（that is, a function pointer&# xff09;，lambda expression.

replace() and replace_if()

template void replace( ForwardIt first, ForwardIt last, const T& old_value, const T& new_value ); //Replace all old_value with new_value in [first,last) range，. Return voidtemplate void replace_if( ForwardIt first, ForwardIt last, UnaryPredicate p, const T& new_value ); // In the [first, last) range ， put all the items that satisfy p The elements of the condition are replaced with new_value. Return void

reverse(begin,end)

Reverses the order of the elements in the range [first ,last).Reverse the order

std::vector myvector;for (int i=1; i<10; & #43;+i) myvector.push_back(i); // 1 2 3 4 5 6 7 8 9std::reverse(myvector.begin(),myvector.end()); // 9 8 7 6 5 4 3 2 1

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