gets在子程序中如何使用

gets在子程序中怎么使用
#include   "stdio.h "
#include <iostream>
using   namespace   std;  
char   rulestr[100][100];
int   rule_no;

void   add_rule()
{
cout < < "Please   type   in   the   rules:\n ";
gets   (rulestr[rule_no]);
rule_no++;  
cout < <rulestr[0];
}


void   main()
{     cout < < "(1).   Add   a   filter   rule:\n ";
cout < < "(2).   Remove   a   filter   rule:\n ";
cout < < "(3).   Display   filter   rules:\n ";
cout < < "(4).   Analyze   filter   rules:\n ";
cout < < "(5).   Exit.\n ";
int   comm_no;
do   {cin> > comm_no;
if(comm_no==1)   add_rule();

}   while   (comm_no!=5);

   
}

为什么子程序调用gets不管用呢？

[解决办法]
#include "stdio.h "
#include <iostream>
using namespace std;
char rulestr[100][100];
int rule_no;

void add_rule()
{
cout < < "Please type in the rules:\n ";
//cout < <rule_no < <endl;;
cin> > (rulestr[rule_no]);
rule_no++;
cout < <rulestr[0] < <endl;;
}


int main()
{
int comm_no;
do {cout < < "(1). Add a filter rule:\n ";
cout < < "(2). Remove a filter rule:\n ";
cout < < "(3). Display filter rules:\n ";
cout < < "(4). Analyze filter rules:\n ";
cout < < "(5). Exit.\n ";
cin> > comm_no;
if(comm_no==1) add_rule();

} while (comm_no!=5);


system( "pause ");
return 0;
}