Is there something wrong here?

[Meatball]

Hey guys, I'm new to programming and I think I'm having some fun...

.. we'll see. I cannot for the life of me figure out what's wrong with my program. It takes a cartesian point as input, and is supposed to describe whether that point on an axis or in some quadrant 1-4. I think all my statements follow syntax, the thing compiles just fine, but it only ever gives me an output of "Your point lies in quadrant I". What's so different about that statement that make that always trumps the conditions I set? Please let me know if you see something wrong here.

Thanks!

-Tyler

//This program finds if a cartesian input point lies on an axis or two, and what quadrant the point is in.

#include<stdlib.h>
#include<stdio.h>
#include<math.h>

int main(void){

double x, y, IQ;

printf("Enter the 'x' coordinate\n");
    scanf("%.2fl", x);
IQ = 0;
    fflush(stdin);

printf("Enter the 'y' coordinate\n");
    scanf("%.2fl", y);

if(y == 0 && x == 0 ) {
    printf("Your point lies on both the x and y axis, and exists within no quadrants");
}
else if ( y == 0 && x == !0 )
    printf("Your point lies on the x axis");
else if ( y == !0 && x == 0 )
    printf("Your point lies on the y axis");
else if ( y > 0 && x > 0 )
    printf("Your point lies in quadrant I");
else if ( y > 0 && x < 0 )
    printf("Your point lies in quadrant II");
else if ( y < 0 && x < 0 )
    printf("Your point lies in quadrant III" );
else if ( y < 0 && x > 0 )
    printf("Your point lies in quadrant IV");

return (0);

}

[laserlight]

This is wrong:

scanf("%.2fl", x);

You should be passing a pointer to x to read into x using %lf not %fl, e.g.,

scanf("%.2lf", &x);

Same goes when reading into y.

Also, this is wrong as fflush is not defined for input streams, or update streams for which the last operation was input:

fflush(stdin);

By the way, I can see that you made effort to indent your code, which is good, but your indentation look inconsistent. I would have indented your code as:

//This program finds if a cartesian input point lies on an axis or two, and what quadrant the point is in.

#include<stdlib.h>
#include<stdio.h>
#include<math.h>

int main(void){

    double x, y, IQ;

    printf("Enter the 'x' coordinate\n");
    scanf("%.2fl", x);
    IQ = 0;
    fflush(stdin);

    printf("Enter the 'y' coordinate\n");
    scanf("%.2fl", y);

    if(y == 0 && x == 0 ) {
        printf("Your point lies on both the x and y axis, and exists within no quadrants");
    }
    else if ( y == 0 && x == !0 )
        printf("Your point lies on the x axis");
    else if ( y == !0 && x == 0 )
        printf("Your point lies on the y axis");
    else if ( y > 0 && x > 0 )
        printf("Your point lies in quadrant I");
    else if ( y > 0 && x < 0 )
        printf("Your point lies in quadrant II");
    else if ( y < 0 && x < 0 )
        printf("Your point lies in quadrant III" );
    else if ( y < 0 && x > 0 )
        printf("Your point lies in quadrant IV");

    return (0);

}

[Adak]

fflush(stdin);

is obsolete. It works only on outgoing streams, not incoming ones.

Imagine your plumbing as in or out streams. Flushing works on OUT streams. You can't flush the kitchen faucet, but you can flush the drain pipe on the kitchen sink.

[Meatball]

Thanks so much guys! I definitely goofed on the placeholders there didn't I.. thank you for the indentation tip. Its better to bump things over to the right another 'tab'?

Question: If fflush(stdin); is so obsolete and not recognized, why does my program not work without it? The buffer gets clogged and the program skips over the 'if' function and just outputs garbage. You never get the chance to enter the second variable.

Thanks again for your help! I really appreciate the helpfulness on this board.

Is there a better way around this?

[Click_here]

The problem is that there is a '\n' still on the buffer

You can get scanf to read '\n' and do nothing with it by adding this to your scanf:

scanf("%.2fl%*c", x);

[iMalc]

Question: If fflush(stdin); is so obsolete and not recognized, why does my program not work without it?

You're probably using an out-of-date compiler which just happens to behave such that that particular command happens to do what you wanted.
Generally though it is an error, albeit a common one, to write that.