validating a float

Is the an easier way, i get errors here

Code:

---

bool valid::validFloat(const std::string& value)
{
        float f;
        std::istringstream strin(value); /* error C2440: 'initializing' : cannot convert from 'std::string' to 'int' */
        strin >> f;
        if (!strin)
                return false;
        else
                return true;
}

---

Did you remember to include the appropriate headers? Other than that I suggest that you post the smallest and simplest program that demonstrates the problem since what you posted looks like it should not result in a compile error.

This is a definite case of MSVC++'s absurd error recovery, and you're missing <sstream>. (There should be three other errors on that line, one of them stating that istringstream is not a member of std or something to that effect.

Anyway, you can just do
return strin;
at the end.

Forgot #include <sstream> ...

Quote:

---

Originally Posted by CornedBee

Anyway, you can just do
return strin;
at the end.

---

you mean..

Code:

---

bool valid::validFloat(const std::string& value)
{
        float f;
        std::istringstream strin(value);
        return strin >> f;       
}

---

?

Or perhaps

Code:

---

return strin >> f && strin.eof();

---

since we not only want a float to be parseable, but it should also be the only thing in the stream.
Note: this fails if you want trailing whitespace to be valid. You could do this:

Code:

---

return strin >> f >> std::ws && strin.eof()

---

May i hijack this thread for another float related...

I'm trying to diplay 2 decimals after a point but this fails

Code:

---

        cout << "Contract Balance Owed " << setprecision (2) << setw(8) << bal << "\n";

---

Any reasons?

You just need additional manipulators. fixed suppresses scientific notation. showpoint makes a point visible even when there is a fractional part of zero.

For example: cout << showpoint << fixed << setprecision(2) << bal << endl;

Quote:

---

Originally Posted by whiteflags

You just need additional manipulators. fixed suppresses scientific notation. showpoint makes a point visible even when there is a fractional part of zero.

For example: cout << showpoint << fixed << setprecision(2) << bal << endl;

---

thanx