Changing the exponent size

[robbiegregg]

Hi all
I am trying to write a bunch of exponential numbers to a file. I can easily change the overall size using setw(x) and setprecision(x) to set the precision. However what I want to do is define how large the exponent is. For example, in my code it outputs an exponential number as 1.2334e+030 - what I want is to output this number as 1.2334e+30. Does anyone have any suggestions?

thanks
Robbie

[ottonhelf]

might be a simple solution, but i would replace all instances of "+0" with "+"

CString result;
result.Replace("+00", "+0");
result.Replace("+0", "+");

Hope that will do the trick for you

[robbiegregg]

Hi

Thanks very much for the reply. Eventually I tried a different approach whereby I have written a simple function which determines what the base and exponent. That way when I write the exponential value to file then I am completely in control:

StructDouble GetDouble(double input)
{
StructDouble returnval;
returnval.val = 0;
returnval.exp = 0;
returnval.sign = 0;


if(input == 0) return returnval;

returnval.val = input;
returnval.exp = 0;
returnval.sign = 0;

while(returnval.val >= 10 || returnval.val < 1)
{
if(returnval.val >= 10)
{
returnval.val /= 10.0;
returnval.exp += 1;
}
else if(returnval.val < 1)
{
returnval.val *= 10.0;
returnval.exp -= 1;
}
else
{
// Okay
}
}
if(returnval.exp < 0)
{
returnval.exp *= -1;
returnval.sign = 1;
}

if(returnval.exp >= 100)
{
returnval.val = 0;
returnval.sign = 0;
returnval.exp = 0;
}

return returnval;
}



where ..

struct StructDouble
{
double val;
int exp;
int sign;
};

To write the exponential out, I do the following:

....
StructDouble temp = GetDouble(outmat.matmatrix[i]);
// Write value (base) - set size depending on size of exponent
if(temp.exp < 10) outf << " " << setw(7) << setprecision(6) << temp.val << "E";
else outf << " " << setw(6) << setprecision(5) << temp.val << "E";
// Write the exponent sign
if(temp.sign == 0) outf << "+";
if(temp.sign == 1) outf << "-";
// Finally write the exponent
outf << temp.exp;
....

I hope this might help someone eventually!!