I'm a newbie of using c++,who can tell me why my program
get crash!
#include <iostream.h>
#include <string.h>
#include <stdlib.h>
const long maxn = 10000;
const long interval = 600;
long block[maxn],i,no,t;
char *p,s[20];
void main()
{
  for (i=0;i<maxn;i++) block[i]=0;
  while (!(cin.eof())) {
    cin.getline(s,19);
    if ((strchr(s,'+')==NULL)&&(strchr(s,'.')==NULL)) break;
    if (!(strchr(s,'+')==NULL)){
      p = s;
      t = atoi(p);
      for (i=0; i<maxn; i++)
    if ((block[i]==0)||(t-block[i]>=interval)) break;
      block[i]=t;
      i++;
      cout<<i<<"\n";
    }
    else {
      p = s;
      t = atoi(p);
      p = strchr(s,'.')+1;
      no = atoi(p);
      no--;
      if ((t-block[no]>=interval)||(block[no]==0)) cout<<'-
'<<"\n";
      else {
    block[no] = t;
    cout<<'+'<<"\n";
      }
    }
  }
}