C + + Primer Fourth Edition reading notes (eight) Order container (cont.)

3.6 Accessing elements

If the container is not empty, then the front and back members of the container type will return a reference to the first or last element within the container.

Accessing the operations of elements within a sequential container

C.back ()	Returns a reference to the last element of container C. If C is empty, the operation is undefined
C.front ()	Returns a reference to the first element of container C. If C is empty, the operation is undefined
C[n]	Returns a reference to an element with the subscript n If N<0 or n>c.size (), the operation is undefined For vector and deque containers only
C.at[n]	Returns a reference to the element labeled N. If the subscript is out of bounds, the operation is undefined For vector and deque containers only

3.7 Deleting an element

Delete an operation of an element in a sequential container

C.erase (P)	Delete the element that the iterator P points to Returns an iterator that points to the element following the deleted element. If P points to the last element within the container, the The returned iterator points to the next position beyond the end of the container. If p itself is pointing to the next position beyond the end Iterator, the function is undefined
C.erase (b, E)	Remove all elements in the range marked by Iterators B and E Returns an iterator that points to the element following the deleted element segment. If e itself is a pointer to the next position beyond the end Iterator, the returned iterator also points to the next position beyond the end of the container
C.clear ()	Removes all elements in container C. return void
C.pop_back ()	Deletes the last element of container C. returns void. If C is an empty container, the function is undefined
C.pop_front ()	Removes the first element of container C. Returns VIOD. If C is an empty container, the function is undefined

3.7.1 Delete First or last element

The Pop_front and Pop_back functions are used to delete the first and last elements within a container. However, the vector container type does not support pop_front operations. These operations delete the specified element and return void.

The return value of the Pop_front and Pop_back functions is not a deleted element value, but void. To get the deleted element value, you must call the front or back function before deleting the element.

3.7.2 Delete an element within a container

The erase operation does not check its parameters. The programmer must ensure that the scope of the iterator or iterator used as a parameter is valid.

3.8 Assignment and Swap

The operator associated with the assignment acts on the entire container. In the swap operation, other operations can be implemented with erase and insert operations. The assignment operator first deletes the elements in the operand container, and then inserts all the elements of the right-operand container into the left container.

C + + Primer Fourth Edition reading notes (eight) Order container (cont.)