vect.push_back("Hello");
vect.push_back("Hi");
vect.push_back("Rasmi");
for(vect<string>::iterator it = vect.begin(); it != vect.end(); ++it)
{
if(*it == "Rasmi") // If it encounters "Rasmi"
{
//it--;
int index = it - vect.begin ();
vect.insert(vect.begin()+2, "Hi");
it = vect.begin () + index;
}
cout << *it;
}

Hello->Hi->Rasmi... The execution becomes successful.