Why am i getting an access violation:

C:\Documents and Settings\jareth\Desktop>dmd -v -w ly2au.d
parse     ly2au
semantic  ly2au
semantic2 ly2au
semantic3 ly2au
code      ly2au
generating code for function 'main'
c:\dmd\bin\..\..\dm\bin\link.exe ly2au,,,user32+kernel32/noi;

C:\Documents and Settings\jareth\Desktop>ly2au
Enter number of light years: 5
Error: Access Violation

Attached is the source code.

On Thu, 11 May 2006 13:35:05 -0400, Robert Jones <robertjones21@HotPOP.com> wrote:

> Why am i getting an access violation:
>
> C:\Documents and Settings\jareth\Desktop>dmd -v -w ly2au.d
> parse     ly2au
> semantic  ly2au
> semantic2 ly2au
> semantic3 ly2au
> code      ly2au
> generating code for function 'main'
> c:\dmd\bin\..\..\dm\bin\link.exe ly2au,,,user32+kernel32/noi;
>
> C:\Documents and Settings\jareth\Desktop>ly2au
> Enter number of light years: 5
> Error: Access Violation
>
> Attached is the source code.

Your scanf is wrong; it takes a pointer to a float, not a real; or you can use %lf for double*.

double tempx;
scanf("%lf", &tempx);
x = tempx;

Robert Jones wrote:
> Why am i getting an access violation:
> 
> C:\Documents and Settings\jareth\Desktop>dmd -v -w ly2au.d
> parse     ly2au
> semantic  ly2au
> semantic2 ly2au
> semantic3 ly2au
> code      ly2au
> generating code for function 'main'
> c:\dmd\bin\..\..\dm\bin\link.exe ly2au,,,user32+kernel32/noi;
> 
> C:\Documents and Settings\jareth\Desktop>ly2au
> Enter number of light years: 5
> Error: Access Violation
> 
> Attached is the source code.
> 
> 
> ------------------------------------------------------------------------
> 
> import std.c.stdio;
> import std.stdio;
> 
>  // number of kilometers in a astronomical unit const real au = 148800000.0;
>  // number of kilometers in a light year based on light second being exactly 300,000km
> const real ly = 9467280000000.0;
> real n;
> real x;
> real y;
> 
> int main()
> in
> {
> 	assert(au is 148800000.0); // ensure that au is exactly 1,448,800,000km
> 	assert(ly is 9467280000000.0); // ensure that ly is exactly 9,467,280,000,000km
> }
> body
> {
> 	writef("Enter number of light years: ");
> 	scanf("%f", x);
> 	
> 	// convert light years to kilometers
> 	y = x * ly;
> 	
> 	 // convert kilometers to astonomical units
> 	n = y / au;
> 	
> 	writefln("\nThe number of astronomical units is %f", n );
> 	return 0;
> }

2 Problems I can see:

1) scanf requires the address of a float, so use &x
2) initialize those reals to some value, or you will get nan

-DavidM

Robert Jones said the following on 5/11/2006 1:35 PM:
Thanks Chris and David, below are the changes to the source which now compiles and does what it is supposed to do.

> 
> import std.c.stdio;
> import std.stdio;
> 
>  // number of kilometers in a astronomical unit const real au = 148800000.0;
const double au = 148800000.0;

>  // number of kilometers in a light year based on light second being exactly 300,000km
> const real ly = 9467280000000.0;
const double ly = 9467280000000.0;

> real n;
double n = 0.0;

> real x;
double x = 0.0;

> real y;
double y = 0.0;

> 
> int main()
> in
> {
> 	assert(au is 148800000.0); // ensure that au is exactly 1,448,800,000km
> 	assert(ly is 9467280000000.0); // ensure that ly is exactly 9,467,280,000,000km
> }
> body
> {
> 	writef("Enter number of light years: ");
> 	scanf("%f", x);
	scanf("%lf", &x);

> 	
> 	// convert light years to kilometers
> 	y = x * ly;
> 	
> 	 // convert kilometers to astonomical units
> 	n = y / au;
> 	
> 	writefln("\nThe number of astronomical units is %f", n );
> 	return 0;
> }