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STL function library

2022-04-23 05:32:00 【Mikawa】

STL

vector

Members of the function	The functionality
begin()	Returns the iterator that points to the first element in the container .
end()	Returns an iterator pointing to the position after the last element of the container , Usually and begin() Use a combination of .
rbegin()	Returns the iterator that points to the last element .
rend()	Returns the iterator pointing to the position before the position of the first element .
cbegin()	and begin() Function the same , It's just based on it , Added const attribute , Cannot be used to modify elements .
cend()	and end() Function the same , It's just based on it , Added const attribute , Cannot be used to modify elements .
crbegin()	and rbegin() Function the same , It's just based on it , Added const attribute , Cannot be used to modify elements .
crend()	and rend() Function the same , It's just based on it , Added const attribute , Cannot be used to modify elements .
size()	Returns the actual number of elements .
max_size()	Returns the maximum number of elements . This is usually a great value , It's usually 232-1, So we rarely use this function .
resize()	Change the number of actual elements .
capacity()	Return to current capacity .
empty()	Determine if there are elements in the container , If there is no element , Then return to true; conversely , return false.
reserve()	Increase the capacity of the container .
shrink _to_fit()	Reduce memory to the size that the current element is actually using .
operator[ ]	Reload the [ ] Operator , You can access the elements in the array as , You can access or even modify... Through subscript vector Elements in the container .
at()	Access elements using a boundary checked index .
front()	Returns the reference to the first element .
back()	Returns the reference to the last element .
data()	Returns a pointer to the first element in the container .
assign()	Replace the original with new elements .
push_back()	Add an element at the end of the sequence .
pop_back()	Remove the element at the end of the sequence .
insert()	Insert one or more elements at the specified location .
erase()	Remove an element or a segment of elements .
clear()	Remove all elements , The container size becomes 0.
swap()	Exchange all elements of two containers .
emplace()	Generate an element directly at the specified location .
emplace_back()	Generate an element at the end of the sequence .

deque

Members of the function	The functionality
begin()	Returns the iterator that points to the first element in the container .
end()	Returns an iterator pointing to the position after the last element of the container , Usually and begin() Use a combination of .
rbegin()	Returns the iterator that points to the last element .
rend()	Returns the iterator pointing to the position before the position of the first element .
cbegin()	and begin() Function the same , It's just based on it , Added const attribute , Cannot be used to modify elements .
cend()	and end() Function the same , It's just based on it , Added const attribute , Cannot be used to modify elements .
crbegin()	and rbegin() Function the same , It's just based on it , Added const attribute , Cannot be used to modify elements .
crend()	and rend() Function the same , It's just based on it , Added const attribute , Cannot be used to modify elements .
size()	Returns the actual number of elements .
max_size()	Returns the maximum number of elements that the container can hold . This is usually a great value , It's usually 232-1, We rarely use this function .
resize()	Change the number of actual elements .
empty()	Determine if there are elements in the container , If there is no element , Then return to true; conversely , return false.
shrink _to_fit()	Reduce memory to the size that the current element is actually using .
at()	Access elements using a boundary checked index .
front()	Returns the reference to the first element .
back()	Returns the reference to the last element .
assign()	Replace the original with new elements .
push_back()	Add an element at the end of the sequence .
push_front()	Add an element to the head of the sequence .
pop_back()	Remove the element at the end of the container .
pop_front()	Remove the element from the head of the container .
insert()	Insert one or more elements at the specified location .
erase()	Remove an element or a piece of element .
clear()	Remove all elements , The container size becomes 0.
swap()	Exchange all elements of two containers .
emplace()	Generate an element directly at the specified location .
emplace_front()	Generate an element at the head of the container . and push_front() Is the difference between the , This function constructs elements directly at the head of the container , Saves the process of copying moving elements .
emplace_back()	Generate an element at the end of the container . and push_back() Is the difference between the , This function constructs elements directly at the end of the container , Saves the process of copying moving elements .

list

Member functions	function
begin()	Returns a bidirectional iterator that points to the first element in the container .
end()	Returns a bidirectional iterator that points to the last element in the container .
rbegin()	Returns the reverse bidirectional iterator pointing to the last element .
rend()	Returns a reverse bidirectional iterator that points to the previous position of the first element .
cbegin()	and begin() Function the same , It's just based on it , Added const attribute , Cannot be used to modify elements .
cend()	and end() Function the same , It's just based on it , Added const attribute , Cannot be used to modify elements .
crbegin()	and rbegin() Function the same , It's just based on it , Added const attribute , Cannot be used to modify elements .
crend()	and rend() Function the same , It's just based on it , Added const attribute , Cannot be used to modify elements .
empty()	Determine if there are elements in the container , If there is no element , Then return to true; conversely , return false.
size()	Returns the number of elements actually contained in the current container .
max_size()	Returns the maximum number of elements a container can contain . This is usually a great value , It's usually 232-1, So we rarely use this function .
front()	Returns the reference to the first element .
back()	Returns the reference to the last element .
assign()	Replace the original contents of the container with new elements .
emplace_front()	Generate an element at the head of the container . This function and push_front() The same function , But it's more efficient .
push_front()	Insert an element in the head of the container .
pop_front()	Delete an element in the container header .
emplace_back()	Generate an element directly at the end of the container . This function and push_back() The same function , But it's more efficient .
push_back()	Insert an element at the end of the container .
pop_back()	Delete an element at the end of the container .
emplace()	Insert the element at the specified position in the container . This function and insert() Function the same , But it's more efficient .
insert()	Insert the element at the specified position in the container .
erase()	Delete an element in one or a region of the container .
swap()	Exchange elements in two containers , You must ensure that the element types stored in the two containers are the same .
resize()	Size the container .
clear()	Delete all elements stored in the container .
splice()	Will a list The element in the container is inserted into the specified location of another container .
remove(val)	Delete all containers equal to val The elements of .
remove_if()	Delete the elements that meet the conditions in the container .
unique()	Delete adjacent duplicate elements in the container , Keep only one .
merge()	Merge two pre ordered list Containers , And after the merger list The container is still in order .
sort()	By changing the position of elements in the container , Sort them .
reverse()	Reverse the order of elements in the container .

map

Member method	function
begin()	Return points to the first... In the container （ Be careful , It's the first one in order ） Bidirectional iterators for key value pairs . If map For containers const limit , The method returns const Two way iterator of type .
end()	Returns the last element pointing to the container （ Be careful , It's the last one in order ） The two-way iterator next to the location , Usually and begin() Use a combination of . If map For containers const limit , The method returns const Two way iterator of type .
rbegin()	Return to last （ Be careful , It's the last one in order ） The inverse bidirectional iterator of the element . If map For containers const limit , The method returns const Reverse bidirectional iterator of type .
rend()	Return to the first （ Be careful , It's the first one in order ） The inverse bidirectional iterator of the previous position of the element . If map For containers const limit , The method returns const Reverse bidirectional iterator of type .
cbegin()	and begin() Function the same , It's just based on it , Added const attribute , Cannot be used to modify key value pairs stored in containers .
cend()	and end() Function the same , It's just based on it , Added const attribute , Cannot be used to modify key value pairs stored in containers .
crbegin()	and rbegin() Function the same , It's just based on it , Added const attribute , Cannot be used to modify key value pairs stored in containers .
crend()	and rend() Function the same , It's just based on it , Added const attribute , Cannot be used to modify key value pairs stored in containers .
find(key)	stay map The search key in the container is key The key/value pair , If you succeed in finding , Returns the bidirectional iterator pointing to the key value pair ; conversely , Then go back and end() Iterators with the same method . in addition , If map For containers const limit , The method returns const Two way iterator of type .
lower_bound(key)	Returns a pointer to the current map The first in the container is greater than or equal to key A two-way iterator of key value pairs . If map For containers const limit , The method returns const Two way iterator of type .
upper_bound(key)	Returns a pointer to the current map The first in the container is greater than key The iterator of the key value pair of . If map For containers const limit , The method returns const Two way iterator of type .
equal_range(key)	This method returns a pair object （ contain 2 Two way iterators ）, among pair.first and lower_bound() The return value of the method is equivalent ,pair.second and upper_bound() The return value of the method is equivalent . in other words , This method will return a range , The keys in this range are key The key/value pair （map The container key value pair is unique , So the range contains at most one key value pair ）.
empty()	If the container is empty , Then return to true; otherwise false.
size()	Returns the current map The number of key value pairs in the container .
max_size()	return map The maximum number of key value pairs a container can hold , Different operating systems , The return values are also different .
operator[]	map The container is overloaded [] Operator , As long as you know map The value of the key of a key value pair in the container , It's like getting elements in an array , Get the corresponding value directly through the key .
at(key)	find map In the container key The value of the key , If you can't find it , This function raises out_of_range abnormal .
insert()	towards map Insert key value pairs into the container .
erase()	Delete map Container designated location 、 Specify key （key） Value or key value pairs in the specified region . The following chapters will focus on this method .
swap()	In exchange for 2 individual map Key value pairs stored in the container , It means , Operation of the 2 Key value pairs must be of the same type .
clear()	Empty map All key value pairs in the container , Even if map Container of size() by 0.
emplace()	At present map Construct a new key value pair at the specified position in the container . The effect is the same as inserting key value pairs , But it's more efficient .
emplace_hint()	In essence and emplace() stay map The way to construct new key value pairs in a container is the same , The difference is , The user must provide the method with an iterator that indicates where the key value pair is generated , As the first parameter of the method .
count(key)	At present map In the container , The search key is key The number of key value pairs and returns . Be careful , because map The key value of each key value pair in the container is unique , Therefore, the maximum return value of this function is 1.

set

Member method	function
begin()	Return points to the first... In the container （ Be careful , It's the first one in order ） Bidirectional iterator of element . If set For containers const limit , The method returns const Two way iterator of type .
end()	Returns the last element pointing to the container （ Be careful , It's the last one in order ） The two-way iterator next to the location , Usually and begin() Use a combination of . If set For containers const limit , The method returns const Two way iterator of type .
rbegin()	Return to last （ Be careful , It's the last one in order ） The inverse bidirectional iterator of the element . If set For containers const limit , The method returns const Reverse bidirectional iterator of type .
rend()	Return to the first （ Be careful , It's the first one in order ） The inverse bidirectional iterator of the previous position of the element . If set For containers const limit , The method returns const Reverse bidirectional iterator of type .
cbegin()	and begin() Function the same , It's just based on it , Added const attribute , Cannot be used to modify element values stored in containers .
cend()	and end() Function the same , It's just based on it , Added const attribute , Cannot be used to modify element values stored in containers .
crbegin()	and rbegin() Function the same , It's just based on it , Added const attribute , Cannot be used to modify element values stored in containers .
crend()	and rend() Function the same , It's just based on it , Added const attribute , Cannot be used to modify element values stored in containers .
find(val)	stay set The lookup value in the container is val The elements of , If you succeed in finding , Returns a bidirectional iterator that points to the element ; conversely , Then go back and end() Iterators with the same method . in addition , If set For containers const limit , The method returns const Two way iterator of type .
lower_bound(val)	Returns a pointer to the current set The first in the container is greater than or equal to val A bidirectional iterator of the elements of . If set For containers const limit , The method returns const Two way iterator of type .
upper_bound(val)	Returns a pointer to the current set The first in the container is greater than val The iterator of the elements of . If set For containers const limit , The method returns const Two way iterator of type .
equal_range(val)	This method returns a pair object （ contain 2 Two way iterators ）, among pair.first and lower_bound() The return value of the method is equivalent ,pair.second and upper_bound() The return value of the method is equivalent . in other words , This method will return a range , The values contained in this range are val The elements of （set Each element in the container is unique , Therefore, the range contains at most one element ）.
empty()	If the container is empty , Then return to true; otherwise false.
size()	Returns the current set The number of elements in the container .
max_size()	return set The maximum number of elements that a container can hold , Different operating systems , The return values are also different .
insert()	towards set Insert element into container .
erase()	Delete set Elements stored in containers .
swap()	In exchange for 2 individual set All elements stored in the container . It means , Operation of the 2 individual set Containers must be of the same type .
clear()	Empty set All elements in the container , But even set Container of size() by 0.
emplace()	At present set Construct the new element directly at the specified location in the container . Its effect and insert() equally , But it's more efficient .
emplace_hint()	In essence and emplace() stay set The way new elements are constructed in containers is the same , The difference is , The consumer must provide the method with an iterator that indicates where the new element is generated , As the first parameter of the method .
count(val)	At present set In the container , The lookup value is val The number of elements of , And back to . Be careful , because set The value of each element in the container is unique , Therefore, the maximum return value of this function is 1.

unordered_map

Member method	function
begin()	Returns a forward iterator pointing to the first key value pair in the container .
end()	Returns a forward iterator pointing to the position after the last key value pair in the container .
cbegin()	and begin() Function the same , It just adds const attribute , That is, the iterator returned by this method cannot be used to modify the key value pairs stored in the container .
cend()	and end() Function the same , It's just based on it , Added const attribute , That is, the iterator returned by this method cannot be used to modify the key value pairs stored in the container .
empty()	If the container is empty , Then return to true; otherwise false.
size()	Returns the number of key value pairs stored in the current container .
max_size()	Returns the maximum number of key value pairs that the container can hold , Different operating systems , The return values are also different .
operator[key]	The template class is overloaded with [] Operator , Its function is to access the elements in the array , Just give the key of a key value pair key, You can get the value corresponding to the key . Be careful , If there is no in the current container with key Is the key value pair of the key , Then it will use this key to insert a new key value pair into the current container .
at(key)	Returns the key stored in the container key Corresponding value , If key non-existent , It will be thrown out. out_of_range abnormal .
find(key)	Looking to key Is the key value pair of the key , If you find , Returns a forward iterator pointing to the key value pair ; conversely , Returns an iterator that points to the position after the last key value pair in the container （ If end() Method return iterator ）.
count(key)	Look in the container to key The number of key value pairs of a key .
equal_range(key)	Return to one pair object , It contains 2 An iterator , Used to indicate that the key in the current container is key The range of key value pairs .
emplace()	Add a new key value pair to the container , Efficient than insert() The method is high .
emplace_hint()	Add a new key value pair to the container , Efficient than insert() The method is high .
insert()	Add a new key value pair to the container .
erase()	Delete the specified key value pair .
clear()	Empty the container , That is, delete all key value pairs stored in the container .
swap()	In exchange for 2 individual unordered_map Key value pairs stored in the container , The premise is that this 2 The types of containers are exactly the same .
bucket_count()	Returns the key value pair stored at the bottom of the current container , Use the bucket （ A linear linked list represents a bucket ） The number of .
max_bucket_count()	Return to the current system ,unordered_map How many barrels can be used at the bottom of the container .
bucket_size(n)	Back to page n The number of key value pairs stored in buckets .
bucket(key)	Return to key Is the key value of the key to the bucket number .
load_factor()	return unordered_map The current load factor in the container . Load factor , It refers to the number of key value pairs stored in the current container （size()） And the number of barrels used （bucket_count()） The ratio of the , namely load_factor() = size() / bucket_count().
max_load_factor()	Returns or sets the current unordered_map The load factor of the container .
rehash(n)	Set the number of buckets used at the bottom of the current container to n.
reserve()	The number of buckets （ That is to say bucket_count() Return value of method ） Set to accommodate at least count Yuan （ Do not exceed the maximum load factor ） The amount needed , And rearrange the container .
hash_function()	Returns the hash function object used by the current container .

stack

Member functions	function
empty()	When stack When there are no elements in the stack , The member function returns true; conversely , return false.
size()	return stack The number of elements stored in the stack .
top()	Returns a reference to a stack top element , The type is T&. If the stack is empty , The program will report an error .
push(const T& val)	Copy first val, then val The copy is pushed to the top of the stack . This is done by calling the underlying container push_back() Function completed .
push(T&& obj)	Push the element into the top of the stack by moving it . This is done by calling the right value reference parameter of the underlying container push_back() Function completed .
pop()	Pop up top element .
emplace(arg…)	arg… It can be a parameter , It can also be multiple parameters , But they are only used to construct an object , And directly generate the object at the top of the stack , As a new stack top element .
swap(stack & other_stack)	Put two stack The elements in the adapter are interchanged , It should be noted that , For exchange 2 individual stack The element types stored in the adapter and the underlying container types , All have to be the same .

queue

Member functions	function
empty()	If queue If there is no element in , return true.
size()	return queue The number of elements in .
front()	return queue Reference to the first element in . If queue Is a constant , Just return a frequent quote ; If queue It's empty , The return value is undefined .
back()	return queue Reference to the last element in . If queue Is a constant , Just return a frequent quote ; If queue It's empty , The return value is undefined .
push(const T& obj)	stay queue Add a copy of the element at the end of . This is by calling the member functions of the underlying container push_back() To complete .
emplace()	stay queue Add an element directly to the tail of the .
push(T&& obj)	In a mobile way queue Add elements to the tail of . This is by calling the member function of the underlying container with the right value reference parameter push_back() To complete .
pop()	Delete queue The first element in .
swap(queue &other_queue)	Put two queue Elements in the container adapter are interchanged , It should be noted that , For exchange 2 individual queue The element types stored in the container adapter and the underlying container types , All have to be the same .

sort

#include <iostream>     // std::cout
#include <algorithm>    // std::sort
#include <vector>       // std::vector
// Implement custom sorting rules in the way of ordinary functions 
bool mycomp(int i, int j) {
    return (i < j);
}
// Implement custom collation as a function object 
class mycomp2 {
public:
    bool operator() (int i, int j) {
        return (i < j);
    }
};

int main() {
    std::vector<int> myvector{ 32, 71, 12, 45, 26, 80, 53, 33 };
    // Call the first syntax format , Yes  32、71、12、45  Sort 
    std::sort(myvector.begin(), myvector.begin() + 4); //(12 32 45 71) 26 80 53 33
    // Call the second syntax format , utilize STL Other comparison rules provided by the standard library （ such as  greater<T>） Sort 
    std::sort(myvector.begin(), myvector.begin() + 4, std::greater<int>()); //(71 45 32 12) 26 80 53 33
   
    // Call the second syntax format , Sorting by custom comparison rules 
    std::sort(myvector.begin(), myvector.end(), mycomp2());//12 26 32 33 45 53 71 80
    // Output  myvector  Elements in the container 
    for (std::vector<int>::iterator it = myvector.begin(); it != myvector.end(); ++it) {
        std::cout << *it << ' ';
    }
    return 0;
}

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