A step-by-step study of STL Standard Template Library

Use of List

The use of the list must include the header file #include <list>

1), how to define a list object

#include <list>
int main (void)
{
　　list<char > cList; //声明了list<char>模板类 的一个实例
}

2, using the member functions of the list push_back and Push_front inserts an element into the list

cList. push_back(‘a’); //把一个对象放到一个list的后面
cList. push_front (‘b’); //把一个对象放到一个list的前面

3, using the member function of list empty () to determine whether the list is empty

if (cList.empty())
{
　　printf(“this list is empty”);
}

4), using list< char >::iterator to get a pointer to the list

list< char>::iterator charIterator;
for(cIterator = cList.Begin();cIterator != cList.end();cIterator++)
{
　　printf(“%c”, *cIterator);
} //输出list中的所有对象

Description: The Clist.begin () and Clist.end () function return a pointer to the list< char >::iterator, which does not support random access because the list uses a linked list structure, and therefore cannot be used with clist.begin () + 3来 points to the fourth object in the list, vector and deque support random access.

5), using the STL General Algorithm count () to count the number of elements in the list

int cNum;
char ch = ’b’;
cNum = count(cList.Begin(), cList.end(), ch); //统计list中的字符b的个数

Note: You must join #include <algorithm> before using the count () function

6), using the general algorithm of STL Count_if () to count the number of elements in the list

const char c (‘c’);
class IsC
{
public:
　　bool operator() ( char& ch )
　　{
　　　　return ch== c;
　　}
};
int numC;
numC = count_if (cList.begin(), cList.end(),IsC());//统计c的数量；

Description: Count_if () takes a parameter of a function object that is a class function object with at least one operator () method that returns true or FALSE when it is agreed to call operator for the STL algorithm. They judge this function according to this. For example, it would be clearer. Count_if () makes a more complex evaluation than count () by passing a function object to determine whether an object should be counted.

7), using the STL general algorithm find () in the list to look up objects

list<char >::iterator FindIterator;
FindIterator = find(cList.begin(), cList.end(), ‘c’);
If (FindIterator == cList.end())
{
　　printf(“not find the char ‘c’!”);
}
else
{
　　printf(“%c”, * FindIterator);
}

Note: If the specified object is not found, the value of Clist.end () is returned, and a pointer to the object iterator is returned if found.