Problem returning double from function

[ragbagger]

I am new to C++ and have a problem. I am compiling code with GCC for an ARM processor and have a function that returns a doubel value. Prototype is:
double TextToFloat(char * stringIn);
Here is the problem: The function works fine if it is part of the file where it is called but if I move it to another file it calculates the return value correctly in the routine but the return statement returns garbage. I figure I must be doing something simple that is wrong but it beats me what it is. ANy help would be appreciated.

[kempofighter]

Post some code otherwise we have no idea what you are talking about.

[ragbagger]

OK, here is the routine:

double TextToFloat(char * stringIn)
{

double number;
unsigned char decimal=0,i=0,sign=0;
unsigned long decimalPlace=10;
number=0;
if (stringIn[0]=='-')
{
sign=1;
i++;
}
while(stringIn[i]!=0)
{
if (stringIn[i]=='.')
{
decimal=1;

}
else
{
if (decimal==1)
{
number=number+(double)(stringIn[i]-48)/decimalPlace;
decimalPlace=decimalPlace*10;
}
else number=number*10+(double)(stringIn[i]-48);
}
i++;
}
if (sign) number=number*-1;
return number;
}

It takes stringIn and turns it into a floating point number. It works fine when defined in the file where it is called but returns garbage when defined in another file.

[Galik]

I have no idea why it should behave differently if placed in a separate file. However there are simpler ways to convert a string to a double:

#include <string>
#include <sstream>

double TextToFloat(const std::string& str)
{
    double d;
    std::istringstream(str) >> d;
    return d;
}

[ragbagger]

Thanks, unfortunately sstream is not supported in this compiler. I did figure out that it works if I change from double to float so it must be something in how it treats the double designation.

[Galik]

Why is sstream missing? Is this an embedded application?

[Galik]

@ ragbagger

I can't find fault with it. Is it possible that the strings you are passing in are somehow doing something? How are you calling this?

EDIT: Passing in a null string will cause a problem though.

[kempofighter]

What about this? That is if you can't use the <sstream> header then use the c-run time library function.
http://cplusplus.com/reference/clibrary/cstdlib/strtod/