Usage record of map ＜ qstring, bool ＞

My application examples are as follows ：

map<QString, bool> m_allSkakFilepath;


auto itpath = m_allSkakFilepath.find(skaPaths.at(n).c_str());
if (itpath !=m_allSkakFilepath.end())
{
	m_allSkakFilepath[skaPaths.at(n).c_str()] = false;
}
else
{
	m_allSkakFilepath[skaPaths.at(n).c_str()] = true;
}

this map Main applications ：

    Usually there are many documents . And you need to find out whether the file is valid , Or used , If used, the flag bit is used as true, It can also be used to determine whether many components have been used , In short, no matter on any occasion , Just for the convenience of searching

      The above code is to add or delete ,map Are the benefits of , Mainly above key It's not worth it map in , If you give the value directly, you will increase one key value

Here is another code for traversing the deletion , The following code is to delete map The median is true, Combined with the meaning of the above paragraph, it means that all the used values are cleared. Remember to clear them iter++：

map<QString, bool>::iterator iter=m_allSkakFilepath.begin();
for(;iter!=m_allSkakFilepath.end();){
	if((*iter).second==true){
		m_allSkakFilepath.erase(iter++);
	}
	else{
		++iter;
	}
} 

map Clean up of ：

// Clearing method 1： Direct will map Deleted 
m_allSkakFilepath.clear();   
//map.clear() Just put map It's empty , But the memory is not released , If you want to free memory, you need more than clear() fall , And an empty map To carry out swap, Free up memory 
// Be careful map If the element is not a basic type , Also release the memory , Like a pointer ,vector Pay special attention to , otherwise map Takes up too much memory , Will cause the program to crash 



// Clearing method 2 use map.erase(map.begin(),map.end()) better    Empty elements 
m_allSkakFilepath.erase(m_allSkakFilepath.begin(),m_allSkakFilepath.end());

// Clearing method 3
map<QString, bool> empty_map1;
m_allSkakFilepath.swap(empty_map1);

Output map size  

 Output map size  
int nsize=m_allSkakFilepath.size();

map Sorting instructions for ：map It defaults to key Sort values in ascending order , Personally, I think it's enough
If you want to traverse in reverse order （ use reverse_iterator The pointer ）：

 for( map<QString, bool>::reverse_iterator rit=m_allSkakFilepath.rbegin();rit!=m_allSkakFilepath.rend();rit++) 
    cout<<(*rit).first<<","<<(*rit).second<<endl;  

modify map The value in , It's easy to change , As long as the key Set it to the corresponding value , as follows : Set up directly key3 from false become true

map<QString, bool> m_allSkakFilepath;
m_allSkakFilepath.insert(("key1", false));
m_allSkakFilepath.insert(("key2", false));
m_allSkakFilepath.insert(("key3", false));
m_allSkakFilepath.insert(("key4", true));

{
    map<QString, bool>::const_iterator iteMap = m_allSkakFilepath.begin();
	cout << "============== Old value result output =============" << endl;
    for(; iteMap != m_allSkakFilepath.end(); ++ iteMap)
    {
        cout << m_allSkakFilepath->first;
        cout << ":";
        cout << m_allSkakFilepath->second << endl;
    }
}

// modify 
m_allSkakFilepath.insert(("key3", true));


{
    map<QString, bool>::const_iterator iteMap = m_allSkakFilepath.begin();
	cout << "============== New value result output =============" << endl;
    for(; iteMap != m_allSkakFilepath.end(); ++ iteMap)
    {
        cout << m_allSkakFilepath->first;
        cout << ":";
        cout << m_allSkakFilepath->second << endl;
    }
}