Is bool a good thing?

It feels to me as though bool is a fundamental data type for computer programming. Storing true or false has obvious practical applications. Yet, some people seem to deprecate bool. It isn't in standard C89. And in any case, bool can be pretty easily simulated like this:

Code:

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typedef bool unsigned int;
#define true 1
#define false 0

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I'd like to use something like this:

Code:

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typedef enum blah { false = 0, true = 1 } bool;

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1. Do you consider bool to be a useful and necessary data type?
2. How does one best simulate/replace bool for a system that doesn't support C99/C++?

Richard

1. Nope
2. enum or #define

Quote:

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Originally Posted by Richardcavell

1. Do you consider bool to be a useful and necessary data type?

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Useful, yes, necessary, no. When I'm working in a language that has them, I'll use the type. In C, I'll just use an int set to 0 or some other number. Some people use hungarian notation like "bVariableName" to indicate bools in C; your method has a little more polish.

Mostly it's ok. But it's hardly necessary in C...

Code:

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int Test(int x)
 { if (x > 10)
      return 1;
  return 0; }


// call
if (!test(myfancytoolongvariablename))
  printf("Dooohh\n");

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It's all nice and neat to define stuff like that but in reality you're just putting lipstick on a pig... nothing new is introduced because it's all still 0 and 1.

Incidentally, even with respect to C99, an expression such as x > 10 results in an int (rather than _Bool, though it is possible that _Bool is int) that is either 0 or 1, so CommonTater's definition of Test could have been simplified to:

Code:

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int Test(int x)
{
    return x > 10;
}

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Quote:

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Originally Posted by laserlight

Incidentally, even with respect to C99, an expression such as x > 10 results in an int (rather than _Bool, though it is possible that _Bool is int) that is either 0 or 1, so CommonTater's definition of Test could have been simplified to:

Code:

---

int Test(int x)
{
    return x > 10;
}

---

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Yep... but I was pretty sure he wouldn't understand it so I went with the more obvious version.

Not necessary in C perhaps, but it can certainly aid readability.
E.g. Say you found some code calling a homemade 'find' function. No code comments are present. Is it returning the index of the item found or is it returning one for found and zero for not found?

Quote:

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Originally Posted by iMalc

Not necessary in C perhaps, but it can certainly aid readability.
E.g. Say you found some code calling a homemade 'find' function. No code comments are present. Is it returning the index of the item found or is it returning one for found and zero for not found?

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That should be easily dscernable from the return statments... return A[index] is pretty much a give away.

Still your point is taken, code with TRUE and FALSE as text is often more explicit than 1 and 0... but that alone should not render it inscrutable.

If you have stdbool.h available it's IMO preferable to defining true/false yourself. At least if used explicitly to compare if something is true. For example:

Code:

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if( test == true )
    // do something

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Works if test is defined as bool, but if test is an int, is only true if test happens to be 1.

Quote:

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Originally Posted by CommonTater

That should be easily dscernable from the return statments... return A[index] is pretty much a give away.

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Oh, I dunno. I reviewed some code a while back which did exactly that. The thing is, the caller had been required to ensure A[index] was either 0 or 1, and nothing else.

A willful programmer can make even simple things inscrutable.

In answer to the original question, bool is useful but not essential. In languages that don't have it, I don't attempt to emulate it.