【求助】求一“排队叫号系统”程序代码

[love1990413]

用户可输入“R”、“S”、“N”，“R”表示用户排队叫号，在当前的排队号后加1，并要输出当前有几个用户在排队，“S”表示服务了一个号码，需求给出的是当前的服务号，“N”表示排队的号又重新从1开始

[coolyama]

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

int main()
{
	vector<int> int_vector;
	char c;
	while ( cin >> c ) {
		switch ( c ) {
			case 'R' :
				{
					int number = int_vector.size();
					int_vector.push_back( number + 1 );
					cout << "now " << int_vector.size() << " people are in the queue including you." << endl;
					break;
				}
			case 'S' :
				{
					if ( int_vector.empty() ) {
						cerr << "No people in queue." << endl;
					}
					else {
						cout << "Number " << int_vector.front() << " has been served." << endl;
						int_vector.erase( int_vector.begin() );
					}
					break;
				}
			case 'N' :
				{
					cout << "warning : queue been cleared!" << endl;
					int_vector.clear();
					break;
				}
		}
	}
	return 0;
}

请使用大写R,S,N