convert float to string

Code:

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        char *output="fps=";
        char tmp[20];


        strcat(output,itoa((int)fps,tmp,2));

---

that's my code, but my program always locks up at the "strcat" section. fps is a float, which i typecasted cuz of "possible loss of data"...see any problems?

I'm trying to get a string that says "FPS=<fps>", but it won't work :(

nevermind, i used sprintf()

In pure C++:

Code:

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ostringstream oss;
oss << "FPS: " << fps_value;

// Do something with oss.str()

---

I'm outputting it to a window i created with CreateWindow()

Code:

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DrawText(hDC, oss.str().c_str(), ...);

---

...or something :)

i think it was textout..yeah here it is:

Code:

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        char *output=new char[];

        sprintf(output,"FPS=%f",fps);
        TextOut(hDC,10,10,output,strlen(output));

---

The thing was i had it output every second, and it showed up for a split second then disappeared...adn reappeared every other second...confusing but yeah.

Then I outputed it in the DrawGL() section, and it did the same thing here

Code:

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char *output=new char[];

---

Uh... :confused:

Not sure how that one can work...

Hey I don't know either...I just know it works.

Should I use

Code:

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char *output = (char *)malloc(255*sizeof(char));

---

instead? I've used that for a while without any problem, so I just stuck with it.

Or do you mean "why does it work he didn't specify a max size"?

I'm just intrigued as to what size buffer you get when you don't give a size - I expect it's compiler dependent.

In C++, use new:

Code:

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char *buffer = new char[255];

---

I'd still use the stringstreams one though, safer and more c++-like (probably just as fast as well, if not faster).

I'm using VC++ 6.0

It doesn't just return 6? (FPS=30) (example)

I'll do a quick thing to check

Yup, I just did quick test, since the number was a float, it came out as


85.00000

so strlen() was 12

Before you insert the float, try something like oss.precision(2);.

ok thanks

what's oss?

i think i'll change it to an int...i dont think the fps will go above 32000 (or whatever the max # for int is)

oss is the ostringstream object from earlier.

The maximum value of an int is about 2 thousand million (4 for unsigned).

Basically, anything you can do to a stream like cout or cin, you can do to a stringstream...that's what makes them so utterly cool :D

Ah. And that works for printf() and scanf()?

I don't think they're particularly compatible with each other, but they do more or less the same thing.

Basically, as printf, scanf, sprintf, sscanf all use a format string, cout, cin, ostringstream, istringstream all use the same manipulators.

For example, if you define operator>> for your class, then it will work with a stringstream :)

<-- C++ n00b
"Basically, as printf, scanf, sprintf, sscanf all use a format string, cout, cin, ostringstream, istringstream all use the same manipulators.

For example, if you define operator>> for your class, then it will work with a stringstream"


:confused:

Ok.

Code:

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printf("Hello: %d\n", int_value_here);

cout << "Hello: " << int_value_here << endl;

---

...or...

Code:

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void thingie(ostream &os) {
    os << 56 << hex << 255 << endl;
}

void somecode() {
    thingie(cout);

    ostringstream oss;
    thingie(oss);

    cout << oss.str();
}

---

All the streams work in the same way, and are interchangeable at the ostream / istream level.

Ohh okay I get it...Thanks :)

No problem.

When you think about it, it's far more logical than C's approach.

yeah, you can customize it alot easier with less code.

Me think's ill use that somewhere...:)