program to check whether point lies on x-axis , y-axis or origin

Question

I have just started learning c programming.

For the question, I wrote the following code. Can you please help me find the error? I am not getting the desired result and the statement in the last else gets executed always.

#include<stdio.h>
#include<conio.h>

void dummy(float *a) 
{
  float b=*a; //perform some floating access
  dummy (&b); //calling a floating point function
}

void main()
{
  double x,y;

  clrscr();

  scanf("%lf %lf",x,y);

  if(x==0 && y!=0)
  { 
    printf("The point lies on the y-axis.");
  }
  else if(y==0 && x!=0 )
  { 
    printf("The point lies on the x-axis.");
  }
  else if(x==0 && y==0)
  { 
    printf("The point is the origin");
  }
  else
  {
    printf("The point lies neither on the x nor the y axis ");
  }
  getch();
}

Please edit your question to include input that causes the faulty behavior, as well as the actual and expected output. — Some programmer dude, Aug 11 '17 at 11:16
hi. whatever be the 2 numbers i enter ,the statement"the point lies neither on the x nor the y axis" gets executed — joey lang, Aug 11 '17 at 11:18
tht's what must happen when you don;t check the return value of scanf. — Sourav Ghosh, Aug 11 '17 at 11:19
Never compare floating point values directly for (un)equality: like it's said here: https://stackoverflow.com/a/4858547/8051589. This may could be the problem. — Andre Kampling, Aug 11 '17 at 11:22
hey andre. i used fabs with both the inequality and the equality cases earlier. but now i used it only with the inequality case and the code works. Thanks — joey lang, Aug 11 '17 at 11:38
It's fortunate you don't use the dummy function since it leads to a crash because it recurses indefinitely. It shouldn't be in the question though. Please read about how to create an MCVE ([MCVE]). — Jonathan Leffler, Aug 11 '17 at 14:05

score 2 · Accepted Answer · 2017-08-11T11:40:49.623

while reading values from keyboard with scanf you need to add & infront of variable.

instead

scanf("%lf %lf",x,y);

Use

scanf("%lf %lf",&x,&y);

Update

you dont have to check every time for both y and x

instead if(x==0 && y!=0) use only one, if(x==0) or if(y==0) Try:

void main()
{
   double x,y;
   clrscr();

   scanf("%lf %lf",&x,&y);

   if(x==0 && y==0)
   { 
       printf("points lies on origin.");
   }
   else if(y==0)
   { 
       printf("points lies on y-axis.");
   }
   else if(x==0)
   { 
       printf("points lies on x-axis");
   }
   else
   {
       printf("The point lies neither on the x nor the y axis ");
   }
   getch();
}

check my answer now, you need to check only `x==0` or `y==0` at a time — , Aug 11 '17 at 11:41

score 1 · Answer 2 · answered Aug 11 '17 at 11:38

1

For to check if is equal use macro or function like

#define FEQUAL(x,y,err)            (fabs((x) - (y)) < (err))

answered Aug 11 '17 at 11:38

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score 1 · Answer 3 · answered Oct 25 '19 at 06:20

Undefined reference to clrscr() function. So, you can try removing clrscr() function from your code.

#include<stdio.h>
#include<conio.h>

void dummy(float *a)
{
  float b=*a; //perform some floating access
  dummy (&b); //calling a floating point function
}

void main()
{
  double x,y;
  scanf("%lf %lf",&x,&y);

  if(x==0 && y!=0)
 {
    printf("The point lies on the y-axis.");
 }
  else if(y==0 && x!=0 )
 {
    printf("The point lies on the x-axis.");
 }
  else if(x==0 && y==0)
 {
    printf("The point is the origin");
 }
  else
 {
    printf("The point lies neither on the x nor the y axis ");
 }
    getch();
 }

It will work.

score 1 · Answer 4 · edited May 17 '20 at 10:41

A simple solution may be as

#include <stdio.h>

int main()
{

    int x,y;
    printf("Enter the point ");
    scanf("%d,%d",&x,&y);
    if (y==0)
    {
        if (x==0)
        {
            printf("\nPonit lies on the origin\n");
        }
        else
            printf("\nPoint lies on X-axis\n");
    }
    else if (x==0)
    {
        if (y==0)
        {
            printf("\nPoint lies on the origin\n");
        }
        else
            printf("\nPoint lies on the Y-axis\n");
    }
    else
        printf("\nPoint lies in X-Y coordinate\n");
    return 0;
}

program to check whether point lies on x-axis , y-axis or origin

4 Answers4