Thread: Data Types

Hey all,

So I am writing a scientific code and thus precision of the numbers I am dealing with is very important. I have a text file as follows containing coordinate data:

Code:

   15.874010519682   15.874010519682   15.874010519682      0.77500000000000
     5.0000000000000D-03
    0.67184753150321   -9.0984212637474  -0.12308571224722
    -7.5391320707008   -5.4421377882969   -3.6434474261884
    -2.8072699927977  -0.27226324050591   0.83267141127818
    -3.4804472086739    1.7404956860775    3.6298663735869
    -6.1997156299320   -8.4300686752649    3.5753823495533

Now I wrote a function to read this data (ignoring the first two lines) and print it out, just so I knew that the code was working correctly. Upon read out I only get:

Code:

 First Line Header: 15.874011 15.874011 15.874011 0.775000 
 Second Line Header: 5.0000000000000D-03

Coords:
0.671848 -9.098421 -0.123086 
-7.539132 -5.442138 -3.643447 
-2.807270 -0.272263 0.832671

Now this is substantial rounding that I need to get rid of. I am using long doubles and I thought the right format identifiers but nothing seems to be working (i.e. no matter what I change I keep getting the rounded numbers). Here is my code:

Code:

void getpoints(void)
{
	if((fp=fopen("daugh.1001","r"))==NULL)
	 {
	 printf("Cannot open file \n");
	 exit(0);
	 }
	
	fscanf(fp,"%Lf %Lf %Lf %Lf\n", &tmp1, &tmp2, &tmp3, &tmp4);
	printf(" First Line Header: %Lf %Lf %Lf %Lf \n",tmp1,tmp2,tmp3,tmp4);
	fgets(tmp, 25, fp);
	printf(" Second Line Header: %s\n",tmp);
	
	for (k=0;k<3;k++)
    {
		fscanf(fp,"%Lf %Lf %Lf \n", &x[k], &y[k], &z[k]);
    }
	
	printf("Coords:\n");
	
	for (k=0;k<3;k++){
		printf("%Lf %Lf %Lf \n", x[k], y[k], z[k]);
	}

}

It's probably something simple... any help you could lend would be greatly appreciated!

Thanks!,
Paddon

Originally Posted by kas2002

It's probably something simple...

Yep. printf() by default rounds to six places. You can make it less this way:

Code:

printf("%.2lf",tmp1);

I myself have never tried making it more than the default, but I assume it will work.