I'm trying to learn how to program in C, so I'm taking my C# programs I did in my computer class and trying to convert them to C using my "The C Programming Language" book. I'm working on a really simple program, but scanf() is giving me a lot of trouble. It works the first time I call it, but the second time I call it, the program just skips right over it and goes to the next statement in my code. I looked it up on google, and I read something that said to try flushall();. I tried that, but it wouldn't compile because that is evidently a Microsoft Visual C specific command, and then I found a webpage that said to try fflush(stdin);. I tried tha too, but it isn't working either. I'm using SuSE 9.1 with GCC version 3.3.3, and here's my code: A suggestion that is intended for GCC and not M$ Write Our Own Version of Every Language Just to Be Different would be very helpful.

#include <stdio.h>

long length, width, perimeter, area;

int main() {
printf("\nApplication: Ch3Prb1 -- Calculate the perimeter and area of a rectange\n\n");
printf("Length: ");
fflush(stdin);
scanf("%ld", &length);
printf("Width: ");
fflush(stdin);
scanf("%ld", &width);

return 0;
}

it seems to work fine for me. (used "gcc t.c" to compile; "./a.out" to run)
how are you running this a "second" time? via an IDE? or on the command line.

doesn't do what you think it does. If there is data in the input stream that data must be read or ignored. fflush() is used for flushing the output buffer, when writing to the screen or the file.
That's why your program is skipping the second scanf() call, you have data left in the input stream after the first call and you must read that data.

That makes sense to me, but what do I have to do to read that data.