input from scanf into structure, how?

[Elite]

Hi, I am making a simple program that asks the user to input 2d points and the program will perform various functions.
This is what I have so far

#include <stdio.h>

struct point2D
{
	float x;
	float y;
};

int main()
{
	point2D pa,pb;

	printf("Please enter the first point: ");
	scanf("%f" "%f", &pa.x, &pa.y);
	printf("Please enter the second point: ");

	return(0);
}

When i enter the first point like so 5 32
i get a runtime error and it says floating point is not loaded.
Am I using the structure wrong or is it the scanf?

Thanks

[quzah]

You could always do a forum search for the message, or perhaps look at what the first hit on a Google search gives you.

Quzah.

[computerfreaks]

you need to declare insances of the structure. You have correctly created the structure, but need instances.

So....

struct point2d pa;
struct point2d pb;

you can then remove the line

point2D pa,pb;

Also change the

scanf("%f" "%f".......

to

scanf("%f %f"......

[quzah]

Actually, no you don't have to. Two string literals will be concatenated into a single literal at compile time. Furthermore, they have declared an instance of their structure, or at least if they're compiling as C++ they have:

struct point2D
{
	float x;
	float y;
};

int main()
{
	point2D pa,pb;

In C they need to simply add the keyword struct to the start of that line.

Neither of these issues are really what they're posting about however.

Quzah.

[computerfreaks]

I stand corrected..... however if this is c++ then surely the message should be posted in the c++ forum??

So are you saying that

scanf("%f""%f", &var1, &var2);

is accepted? ok... just tested and it is, but still, it seems like bad practice to put this...

therefore the code should be (if C ):

#include <stdio.h>

struct point2D
{
	float x;
	float y;
};

int main()
{
	struct point2D pa,pb;

	printf("Please enter the first point: ");
	scanf("%f" "%f", &pa.x, &pa.y);
	printf("Please enter the second point: ");
	
	system("pause");

	return(0);
}

[quzah]

Sure, it should be compiled as C. However, since they didn't say they were getting any other errors, such as:

suchas.c: In function `main':
suchas.c:11: error: `point2D' undeclared (first use in this function)
suchas.c:11: error: (Each undeclared identifier is reported only once
suchas.c:11: error: for each function it appears in.)
suchas.c:11: error: parse error before "pa"
suchas.c:14: error: `pa' undeclared (first use in this function)

Then it's obvious they're compiling as C++ and not C. But again, that has nothing to do with their floating point problem.

Quzah.

[ronenk]

this form seem clearer to me.

#include <stdio.h>

typedef struct 
{
	float x;
	float y;
}point2D;

int main()
{
	point2D pa;

	printf("Please enter the first point: ");
	scanf("%f" "%f", &pa.x, &pa.y);
	printf("Please enter the second point: ");
	
	system("pause");

	return(0);
}

still, it gives same runtime error .

[Dave_Sinkula]

still, it gives same runtime error .

Wrong band-aid:
https://cboard.cprogramming.com/showthread.php?p=322171

[Which is the same thing you'll find if you follow quzah's link.]

[Salem]

> scanf("%f""%f", &var1, &var2);
> is accepted?
Yes, the compiler will automatically join "hello " "world" into "hello world" for you.

Not a lot of use here, but dead handy if you're trying to create some help text and you don't want your source code to look a mess.