question

[elrookie]

here is a

*/
 * reverse polish calculator
 */

#include <stdio.h>
#include "calc.h" /* header file */
#include <math.h>
#include <stdlib.h>

#define MAXOP 100

main()
{
  int type;
  int op2;
  char s[MAXOP];
  
  while ((type = getop(s)) != EOF) 
    {
      switch(type) 
	{
	case NUMBER:
	  push(atof(s));
	  break;

        /* case '^':
          push(pop()^pop());
          break; */

        case '~':
          op2 = pop();
          push(pop() ~ op2);
          break;
          
	case '+':
	  push(pop() + pop());
	  break;
	case '*':
	  push(pop() * pop());
	  break;
        case '-':
	  op2 = pop();
	  push(pop() - op2);
	  break;

        case '%':
          op2 = pop();
          if(op2)
          push(fmod(pop(), op2));
          else
          printf("\nError: Division by zero!");
          break;


	case '/':
	  op2 = pop();
	  if (op2 != 0.0)
	    push(pop() / op2);
	  else 
	    {
	      printf("error : zero divisor\n");
	      exit(1);
	    }
	  break;
	case '\n':
	  printf("The answer is %.8g.\n", pop());
	  break;
	default:
	  printf("error: unknown command %s\n", s);
	  exit(1);
	}
    }
}

looking at this part of the code I'm doing something wrong

        case '^':
          push(pop()^pop());
          break; 

        case '~':
          op2 = pop();
          push(pop() ~ op2);
          break;

i am getting

"parser error before '~' token
main.o error 1
"parser error before '^' token
main.o error 1

i am trying to add these binary operations to the RPN calculator, what's wrong here?

[laserlight]

hmm... but ~ is a unary, not binary (dyadic) operator.

[Prelude]

>push(pop() ~ op2);
~ isn't a binary operator, it's a unary operator.

>push(pop()^pop());
Can you show us how you've defined pop?

[robwhit]

the ~ operator is a unary operator, meaning it only takes one variable. You're using it as a binary operator, which is one that uses two variables.

unary: ! var
unary: - var
binary: var + var1
binary: var && var1

also, name your file main.c, not main.o

[elrookie]

#define NUMBER '0'

void push(double);
double pop(void);
int getop(char[]);
int getch(void);
void ungetch(int);

so how can I include these unary operators so that the calculator is able to perform these bit operations?

and i changed my main.o to main.c. Thanks for the reponses

[Prelude]

>double pop(void);
That's your problem. ^ is a bitwise operator, and bitwise operators can't be used with floating-point values. I'm guessing you were trying to do x to the power of y rather than x XOR y. Try calling the pow function from math.h instead.

[elrookie]

ohhh thanks guys now it works... !