main.c

Multi-module programs and MAKE

#include <stdio.h>
#include "getop.h"              /* getop header file */
#include "stack.h"		/* stack header file */
/* math.h not needed in this version, since atof isn't being used
   and atoi is not declared there--try "grep atoi /usr/include/math.h" */

#define MAXOP 100

main()
{
    int type, op2;
    char s[MAXOP];

    while ((type = getop(s)) != EOF)
    {
	switch(type)
	{
	    case NUMBER:
		push(atoi(s));
		break;
            case '+':
		push(pop() + pop());
		break;
            case '*':
		push(pop() * pop());
		break;
            case '-':
		op2 = pop();
		push(pop() - op2);
		break;
            case '/':
		op2 = pop();
		if (op2 != 0)
		    push(pop() / op2);
                else
		    printf("error : zero divisor\n");
                break;
   /* added for hw4: bitwise or, and, not */
            case '|':		/* bitwise or */
		push(pop() | pop());
		break;
            case '&':		/* bitwise and */
		push(pop() & pop());
		break;
            case '~':		/* bitwise not, i.e., 1's complement */
		push(~pop());
		break;
   /* end of new code */
            case '\n':
		printf("The answer is %d.\n", pop());
		break;
            default:
	        printf("error: unknown command %s\n", s);
		break;
            }
       }
}