int i,n,ii;
char sym;         /** current symbol **/
char input[100];  /** input string **/
char stack[100];  /** history stack **/
int spoint=0;     /** stack pointer **/
out(){
  for(ii=0;ii<=spoint;ii++)printf("%c ",stack[ii]);
  for(ii=spoint+1;ii<=5;ii++)printf("%c ",' ');
  for(ii=1;ii<=i-1;ii++)printf("%c ",' ');
  for(ii=i;ii<=n;ii++)printf("%c ",input[ii]);
  for(ii=1;ii<=3;ii++)printf("%c ",' ');
}
push(char x){
  printf("enter %c",x); getchar();
  spoint++; stack[spoint]=x;
  out(); 
}
pop(char x){
  printf("exit from %c",x); getchar();
  spoint--; out();
}
error(){};
getsym(){
  if(i!=0)printf("consume %c ",sym); getchar();
  i++; sym=input[i]; out(); 
}
X(){
  push('X');
  S();
  if(sym=='!')getsym(); else error();
  pop('X');
}
S(){
  push('S');
  if(sym=='('){getsym(); S(); 
               if(sym==')')getsym(); else error();
               S();}                /** change here **/
  else if(sym=='#'); else error();  /** change here **/
//  else printf("( expected\n");    /** change here **/
  pop('S');
}
main(){
  printf("Input string followed by !\n");
  ii=0; do {ii++; scanf("%c",&input[ii]);} while(input[ii]!='!');    
  n=ii;
  printf("Keep hitting return key\n");
  getchar();
  stack[0]='#';
  i=0; getsym();
  X();
  if(spoint==0)printf("accept\n");
          else printf("reject\n");
}
/*** sample session, # stack bottom, ! string end marker 
a.out
Input string followed by !
(())!
Keep hitting return key

#           ( ( ) ) !       enter X
# X         ( ( ) ) !       enter S
# X S       ( ( ) ) !       consume ( 
# X S         ( ) ) !       enter S
# X S S       ( ) ) !       consume ( 
# X S S         ) ) !       enter S
# X S S S       ) ) !       exit from S
# X S S         ) ) !       consume ) 
# X S S           ) !       enter S
# X S S S         ) !       exit from S
# X S S           ) !       exit from S
# X S             ) !       consume ) 
# X S               !       enter S
# X S S             !       exit from S
# X S               !       exit from S
# X                 !       consume ! 
# X                         exit from X
#                           accept

*/