运行代码：

//map求和accumulate、参数互换
#include"std_lib_facilities.h"

istream& operator>>(istream& is, map<string, int>&mm)
{
	string ss="";
	int ii=0;
	is >> ss;
	if(is>>ii)mm[ss] = ii;
    return is;
}

template<class T,class A>
ostream& operator<<(ostream& os,  map<T, A>& mm)
{
	for ( typename map<T, A>::iterator it = mm.begin(); it != mm.end(); it++)
	{
		os << "( " << it->first << " , " << it->second << " )" << "\n";
	}
	return os;
}

int& accumulate_map(map<string, int>mm,int& sum)
{
	for (map<string, int>::iterator p = mm.begin(); p != mm.end(); p++)
		sum += p->second;
	return sum;
}

void msi_to_mis(map<string, int>& msi, map<int, string>& mis)
{
	for (map<string, int>::iterator p = msi.begin(); p != msi.end(); p++)
	{
		mis[p->second] = p->first;
	}
}

int main()
try
{
	map<string, int>msi;

	msi["lecture"] = 21;
	msi["Max"] = 23;
	msi["Jane"] = 24;
	msi["Tom"] = 33;
	msi["Sun"] = 55;
	msi["lecccture"] = 213;
	msi["Maddx"] = 233;
	msi["Janeee"] = 4;
	msi["Tomd"] = 343;
	msi["Sude"] = 25;

    map<string, int>::iterator p = msi.find("Sun");
	msi.erase(p);

	cout << msi<<"\n";

	int sum = 0;
	sum = accumulate_map(msi, sum);
	cout << sum<<"\n\n";

	map<int, string>mis;
	msi_to_mis(msi, mis);

	cout << mis<<"\n";

	return 0;
}
catch (exception& e) {
	cerr << "error:" << e.what() << '\n';
	keep_window_open();
	return 1;
}
catch (...) {
	cerr << "Oops:unknown exception!\n";
	keep_window_open();
	return 2;
}

运行结果：