C++如何使用迭代器从Set中删除一系列值

C++如何使用迭代器从Set中删除一系列值

给定一个Set,任务是使用Iterator从该Set中删除一系列值。

例子:

输入:set = [10 20 30 40 50 60 70 80 90],
              start_iterator = 3,
              end_iterator = 8
输出:10 20 80 90

输入:set = [1 2 3 4 5],
              start_iterator = 1,
              end_iterator = 3
输出:3 4 5

过程: 在这种方法中,从集合中删除一系列元素。这是通过两个迭代器的帮助完成的。第一个迭代器指向范围的起始元素,第二个迭代器指向范围的最后一个元素。第一个迭代器是 排他的 而最后一个迭代器是 全包含的 这意味着最后一个迭代器所指的元素也将被删除。

语法:

iterator erase (const_iterator startPositionIterator_exclusive, 
                const_iterator endingPositionIterator_inclusive);

下面是以上方法的实现:

程序:

// C++ program to delete an element
// of a Set by passing its value
  
#include <iostream>
#include <set>
using namespace std;
  
// Function to print the set
void printSet(set<int> myset)
{
  
    // Get the iterator
    set<int>::iterator it;
  
    // printing all the elements of the set
    for (it = myset.begin(); it != myset.end(); ++it)
        cout << ' ' << *it;
    cout << '\n';
}
  
// Function to delete the element of set
void deleteRange(set<int> myset)
{
  
    // printing all the elements of the set
    cout << "\nSet originally: ";
    printSet(myset);
  
    // Get the starting Iterator at 3rd element
    set<int>::iterator start_itr = myset.begin();
    start_itr++;
    start_itr++;
  
    // Get the ending Iterator at 2nd last element
    set<int>::iterator end_itr = myset.end();
    end_itr--;
    end_itr--;
  
    // Erase the elements in the range
    // of the iterators passed as the parameter
    myset.erase(start_itr, end_itr);
  
    // printing all the elements of the set
    cout << "Set after deletion of range"
         << " from 3rd till 2nd last: ";
    printSet(myset);
}
  
// Driver code
int main()
{
    set<int> myset;
  
    // Get the set
    for (int i = 1; i < 10; i++)
        myset.insert(i * 10);
  
    // Delete an element from the Set
    deleteRange(myset);
  
    return 0;
}
Set originally:  10 20 30 40 50 60 70 80 90
Set after deletion of range from 3rd till 2nd last:  10 20 80 90

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