Double conversion string

Question

I have the following code:

FILE *fp;
double Data[9][7];
int i=0,k;                  
fp = fopen ( "dstest 2.mod", "r" ) ;
fscanf(fp, "%E %E %E %E %E %E %E*[ ]",
           &Data[i][0],
           &Data[i][1],
           &Data[i][2],
           &Data[i][3],
           &Data[i][4],
           &Data[i][5],
           &Data[i][6] );

But whenever I run it I get the following warnings:

Read.c:12: warning: format ‘%E’ expects type ‘float *’, but argument 3 has type ‘double *’

And it goes for all the arguments (Data[i][j]). I have no idea what's wrong. The problem goes away when I use float Data instead of double data. But that will not fit in my requirements.

Answer 1

%E works with floats; for doubles you have to use %lE.

Sadly, inconsistency between the printf and the scanf here is not helping (printf does not support floats since all variadic arguments of type float are implicitly converted to double, but scanf does make a difference between the two FP types)

Answer 2

man scanf says that you need the l modifier character to read a double:

fscanf(fp, "%lE %lE...

and so on.

Answer 3

Use %lE to specify a double instead of a float.