Hello,
Okay, I have another question for yall. I am having a little problem going from string to double.
I am trying to use this function

strtod

My string name it t1
and my double name is n1

this is what I have, but i know it does not work
n1=strtod(t1);

if I was going to long I could just do
n1=atol(d,t1);
but I am not.

Yes I know it is not good practice to use such common names at t1 and n1, but this is just testing purposes, I will put this into play, later.

Okay thanks for the help.
~Ronald

The problem is that strtod() is a function that has been around since the original C. C didn't have strings as we know it (a class which contains the characters), instead strings were character arrays, with the end being denoted by the a NULL terminator (\0).

So, in plain C, to get a string, you'd have

char[] word = {'h', 'e', 'l', 'l', 'o', '\0'};

These were pretty dodgy, since the only way to know the end of a string was to see the NULL character at the end. If the \0 is overwritten (and it can happen pretty easily), then the memory is continually read until a NULL character is found, getting a load of rubbish along the way. And writing to this would overwrite memory needed elsewhere, crashing all.

C++ improved this drastically, with the string class, which stores the length of the string along with a character array - so it doesn't rely on a NULL character.

However (getting back to the point), strtod() function only can accept C style strings, i.e. character arrays. You can convert a C++ string to a C string using a method of the string class, c_str().

word.c_str() - returns a character array with a NULL at the end.

So to answer your question, the syntax to get that working is:

Hope this helps
GF

That is extremely helpful

Okay, I have another question for yall. I am having a little problem going back from double to string.

I am currently saving to a text file then reading it back, but I don't like this away at all. Could you show me an easier way please.

Okay thanks for the help.
~Ronald



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