#include <ctype.h>
#include <stdio.h>
/*
 * From Figure 4.1, pp. 82, Programming Languages
 * by Ken Louden
 */

typedef enum {PLUS, TIMES, LPAREN, RPAREN,
              EOL, NUMBER, ERROR} TokenType;
			  
int numval;
int curr_char;

TokenType getToken( void ){
	while( (curr_char = getchar() ) == ' ');
	if( isdigit( curr_char ) ) {
		numval = 0;
		while( isdigit( curr_char ) ){
			numval = 10 * numval + curr_char - '0';
			curr_char = getchar();
		}
		ungetc( curr_char, stdin );
		return NUMBER;
	}
	
	else {
		switch( curr_char ) {
			case '(':  return LPAREN; break;
			case ')':  return RPAREN; break;
			case '+':  return PLUS;   break;
			case '*':  return TIMES;  break;
			case '\n': return EOL;   break;
			default:   return ERROR;  break;
		}
	}
}

main() {
	TokenType token;
	do {
		token = getToken();
		switch( token ) {
			case PLUS:   printf( "PLUS\n" ); break;
			case TIMES:  printf( "TIMES\n" ); break;
			case LPAREN: printf( "LPAREN\n" ); break;
			case RPAREN: printf( "RPAREN\n" ); break;
			case EOL:    printf( "EOL\n" ); break;
			case NUMBER: printf( "NUMBER: %d\n", numval ); break;
			case ERROR:  printf( "ERROR: %c\n", curr_char); break;
		}
	} while( token != EOL );
	return 0;
}