Infinite printf()

AH it just clicked! I get it now. Thanks everybody.

instead of clearing input using getchar - it is possible to use
fgets/sscanf instead, and avoid clearing problem at all

Quite nice -- I think the only thing I would have done differently would be to use size_t in a few places instead of int, because sizeof evaluates to values of type size_t. Note that if you had compiler warnings enabled it would probably warn you about signed/unsigned type mismatches, because size_t is an unsigned type and int is a signed type (and thus comparing them as in "i < sizeof(item)/sizeof(*item)" might not work for very large or negative values).

What vart says is true, too. The fgets method would probably make your life easier in the end.

Code:

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char buffer[BUFSIZ];  /* BUFSIZ is a constant defined in stdio.h, at least 512 in size */

while(fgets(buffer, sizeof buffer, stdin)) {
    if(sscanf(buffer, "%d", &number) == 1) {
        printf("%d\n", number);
    }
    else {
        printf("Error: please enter a number\n");
    }
}

---

That's all there is to handling EOF and everything.

I get no warnings whatsoever. I checked my compile settings in regards to warnings and even checked everything that was available for checking. Still no warnings.

Where does the newline come from in

Code:

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while(getchar() != '\n') {}

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?

do you feed a \n into input when you press enter? I thought that was called a carriage return?

> do you feed a \n into input when you press enter?

yes.

> I thought that was called a carriage return?

that's \r. When you press enter, some machines give a \n, some an \r, some an \r\n. But on text streams (as opposed to binary streams) like stdin, the newline sequence is always translated to \n.

Quote:

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I get no warnings whatsoever. I checked my compile settings in regards to warnings and even checked everything that was available for checking. Still no warnings.

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That's strange. Here's what I get. The blue warning is the one I was talking about.

Code:

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$ gcc -pedantic -W -Wall dino1.c -o dino1
dino1.c:49:3: warning: C++ style comments are not allowed in ISO C90
dino1.c:49:3: warning: (this will be reported only once per input file)
dino1.c: In function ‘main’:
dino1.c:51: warning: comparison between signed and unsigned

---

If you can add warning flags directly, I suggest -W and -Wall. (If you put -ansi and -pedantic, it will always warn about single-line comments. Unless you use -std=c99.)