#include <stdio.h>
int main()
{
int s[9999] ;
scanf("%s", &s);
printf("hello, %s\n", s);
return 0 ;
}

line 5: scanf( "%s",s );

this program can only executed once, try this loop:

     while(scanf("%s",s)!=EOF){

        //put your program here

     }

this loop will wait until the user input a string,then the code will repeat again and again

*i'm sorry that i can't reply you by using chinese,the linus don't let me change language  :(