访问地图的分段错误C ++

Question

In continuation to this question I am trying to access a map. But i am getting a segmentation fault. Below is my code:

typedef multimap<string, vector<string> > mos_map;
typedef multimap<string, vector<string> >::iterator mos_map_it;

int main()
{

mos_map mos;
mos_map_it it;

vector<string> v1;

v1.push_back("a");
v1.push_back("b");
v1.push_back("c");
v1.push_back("mo1");

mos.insert(mos_map::value_type(*(v1.end()-1),v1));

for(it=mos.begin();it!=mos.end();it++);
{
cout<<(*it).first<<endl;//seg fault occurs here
}

Answer 1

for(it=mos.begin();it!=mos.end();it++);
//                                    ^

Your loop has empty body.

Some tips:

• Enable warnings:

  warning: for loop has empty body [-Wempty-body]

• Declare variables only when they are needed:

   for(auto it = mos.begin(); it != mos.end(); it++); { cout << (*it).first << endl; } 

  This code will cause a compile time error:

  error: use of undeclared identifier 'it'