handle_opt.c

在linux/UNIX上

/*
*handle_opt.c
*		define the function declared in handle_opt.h;
*AUTHOR:[e-mail];
*VERSION:1.0;
*DATE:2006-8-9;
*/

#include "handle_opt.h"

/*define the operator's PRI
*OPERATOR:    (		^	*	+-	)
*PRI:	   	  8		6	4	2	1
*@PARAM:a operator;
*@RETURN:the operator's PRI;
*DATE:2006-8-8;
*/
int operator_pri(char operator)
{
	char opr = operator;

	switch (opr)
	{
		case '(' : return 8;
		case '^' : return 6;
		case '/' : 
		case '*' : return 4;
		case '+' :
		case '-' : return 2;
		case ')' : return 1;
		default:printf("Undefined operator: %c.\n", opr); break;
	}
}

/*handle the operator '(' */
void handle_left_b(char operator)
{
	push(&operator_stack, operator);
}

/*handle the operator '^' */
void handle_pow(char operator)
{
	push(&operator_stack, operator);
}

/*handle the operator '*' and '/' */
void handle_multi(char operator)
{
	int val;
	char opt = operator;
	
	if (!is_empty(&operator_stack))
		{
			push(&operator_stack, opt);
			return;
		}
	
	char opt_instack = sp_value(&operator_stack); 
	
	if (operator_pri(opt_instack) >= operator_pri(opt))
	{
		switch (opt_instack)
		{
			case '(' : push(&operator_stack, opt);break;
			case '*' : 
			{
				val = pop(&oprand_stack);
				val *= pop(&oprand_stack);
				push(&oprand_stack, val);
				pop(&operator_stack);
				push(&operator_stack, opt);
				break;
			}
			case '/' :
			{	
				val = pop(&oprand_stack);
				val = pop(&oprand_stack) / val;
				push(&oprand_stack, val);
				pop(&operator_stack);
				push(&operator_stack, opt);
				break;
			}
			case '^' :
			{
				int tmp = pop(&oprand_stack);
				val = pop(&oprand_stack);
				val = (int)pow(val, tmp);
				push(&oprand_stack, val);
				pop(&operator_stack);
				handle_multi(opt);
				break;
			}
			default : break; 
		}
	}
	else
	{
		push(&operator_stack, opt);
	}
}

/*handle the '+'and '-'*/
void handle_add_and_sub(char operator)
{
	int val;
	char opt = operator;
	
	if (!is_empty(&operator_stack))
		{
			push(&operator_stack, opt);
			return;
		}
	
	char opt_instack = sp_value(&operator_stack); 
	
	if  (operator_pri(opt_instack) >= operator_pri(opt))
	{
		switch (opt_instack)
		{
			case '(' : push(&operator_stack, opt); break;
			case '*' : 
			{
				val = pop(&oprand_stack);
				val *= pop(&oprand_stack);
				push(&oprand_stack, val);
				pop(&operator_stack);
				handle_add_and_sub(opt);
				break;
			}
			case '/' :
			{	
				val = pop(&oprand_stack);
				val = pop(&oprand_stack) / val;
				push(&oprand_stack, val);
				pop(&operator_stack);
				handle_add_and_sub(opt);
				break;
			}
			case '^' :
			{
				int tmp = pop(&oprand_stack);
				val = pop(&oprand_stack);
				val = (int)pow(val, tmp);
				push(&oprand_stack, val);
				pop(&operator_stack);
				handle_add_and_sub(opt);
				break;
			}
			case '+' :
			{	
				val = pop(&oprand_stack);
				val += pop(&oprand_stack);
				push(&oprand_stack, val);
				pop(&operator_stack);
				push(&operator_stack, opt);
				break;
			}
			case '-' :
			{	
				val = pop(&oprand_stack);
				val = pop(&oprand_stack) - val;
				push(&oprand_stack, val);
				pop(&operator_stack);
				push(&operator_stack, opt);
				break;
			}
			default : break; 
		}
	}	
	else
	{
		push(&operator_stack, opt);
	}
}

/*handle the ')' ; 
*	when we meet ')', we handle the stack until meet '(';
*/
void handle_right_b(char operator)
{
	int val;
	char opt = operator;
	
	if (!is_empty(&operator_stack))
		{
			printf("Wrong:NO operator in stack but you put a ')'!\n");
			return;
		}
	
	char opt_instack = sp_value(&operator_stack); 
	
	switch (opt_instack)
	{
		case '(' : pop(&operator_stack); break;
		case '*' : 
		{
			val = pop(&oprand_stack);
			val *= pop(&oprand_stack);
			push(&oprand_stack, val);
			pop(&operator_stack);
			handle_right_b(opt);
			break;
		}
		case '/' :
		{	
			val = pop(&oprand_stack);
			val = pop(&oprand_stack) / val;
			push(&oprand_stack, val);
			pop(&operator_stack);
			handle_right_b(opt);
			break;
		}
		case '^' :
		{
			int tmp = pop(&oprand_stack);
			val = pop(&oprand_stack);
			val = (int)pow(val, tmp);
			push(&oprand_stack, val);
			pop(&operator_stack);
			handle_right_b(opt);
			break;
		}
		case '+' :
		{	
			val = pop(&oprand_stack);
			val += pop(&oprand_stack);
			push(&oprand_stack, val);
			pop(&operator_stack);
			handle_right_b(opt);
			break;
		}
		case '-' :
		{	
			val = pop(&oprand_stack);
			val = pop(&oprand_stack) - val;
			push(&oprand_stack, val);
			pop(&operator_stack);
			handle_right_b(opt);
			break;
		}
		default : break; 
	}
}