Floating Point Exception

ascii (1062)
Hey, can anyone tell me why I'm getting a floating point exception in the following C program? The program will run fine if I give it an expression without any parenthesis, but if there are parantheses I get a floating point exception in the function MultiplyDivide (sorry I couldn't think of a better name :/) Here's the relevant code, if you want me to post the rest I will :)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
 
int GetNext(char s[]) {
    if(s[i] == '(') 		/* if parantheses are found */
	return '(';
    else if(s[i] == ')') 
	return ')';
    int sign = (s[i-1] == '-') ? -1 : 1;   /* if the number is negative */
    int digit = 0;
    if(isdigit(s[i])) {	/* grab the number */
	while(isdigit(s[i])) {
	    digit = 10 * digit + (s[i] - '0');
	    ++i;
	}
    }
    if(s[i] == '*' || s[i] == '/') 
	return MultiplyDivide(s, digit, sign);
    return digit * sign;
}

int MultiplyDivide(char s[], int digit, int sign) {
    if(s[i] == '*') {
	++i;
	return GetNext(s) * (digit * sign);
    }
    else if(s[i] == '/') {
	++i;
	return GetNext(s) / (digit * sign);
    }
    else 			/* if there was an error... */
	PrintError(s, "MultiplyDivide");
}

int open = 0, close = 0;       /* number of opening and closing parantheses */
int Parantheses(char s[]) {
    ++open;
    int total = 0;		/* total value of the parantheses */
    while(open != close) {
	int digit = GetNext(s);
	if(digit == '(') {	/* if there is an opening or closing paren */
	    ++open;
	    ++i;
	    total += Parantheses(s);
	}
	else if(digit == ')') {
	    ++close;
	    ++i;
	}
	else {
	    total += digit;
	    ++i;
	}
    }
    return total;
}


Thanks :)

P.S. Feel free to rip on bad coding style and the likes as well :)
Last edited on
Ben D (1)
I haven't looked at your code very closer, but it could be division by zero. You should check that.
Cheers.
ascii (1062)
Yeah I realized that. When I was looking up the problem I determined that at some point in MultiplyDivide I was dividing by zero.
ascii (1062)
bump, I'm stumped on this!
Duthomhas (13281)
What is the expression you are feeding into this?

(Remember that integer division does not produce numbers with fractional parts.)
ascii (1062)
Any expression with parentheses! For example, the expression: (4 + 5) * 6 will cause a floating point exception.
helios (17607)
Hmm... What exactly is controlling the recursion here? For example, if s="(1)*1", it looks like GetNext(s) will call MultiplyDivide(s) at the end, which will call GetNext(s), and so on. No state about the parsing progress seems to be kept.
Topic archived. No new replies allowed.