目的：全部删除'f'
问题：循环中断，无法全部删除
#include<iostream>
#include<map>
using namespace std;
int main()
{
    map<int, char> m1;
    m1[10010] = 'm';
    m1[10011] = 'f';
    m1[10012] = 'f';
    m1[10013] = 'm';
    m1[10014] = 'f';
    m1[10015] = 'm';
    //删除'f'
    for(int i = 10010; i < m1.size()+10010; i++)
    {
        cout << i << " ";
        //到第3次就中断了
        if(m1[i] == 'f')
        {
            m1.erase(i);
        }
    }
    //输出结果
    for(map<int, char>::iterator it = m1.begin(); it != m1.end(); it++)
    {
        cout << it->second << " ";
    }
    cout << endl;
}

当你 m1.erase(i) 后，有没有想过 m1.size()+10010 中的 m1.size() 会变化？

#include <iostream>
#include <map>
using namespace std;

int main( void )
{
    map<int,char> m1 = { {10010,'m'}, {10011,'f'}, {10012,'f'}, {10013,'m'}, {10014,'f'}, {10015,'m'} };

    //删除 'f'
    for( auto itor=m1.begin(); itor!=m1.end(); )
    {
        if( itor->second == 'f' )
            itor = m1.erase( itor );
        else
            ++itor;
    }

    //输出结果
    for( const auto& p : m1 )
        cout << p.second << ' ';
    cout << endl;
}