Thread: ftoa??? Is there a direct way to convert a float to a string?

  1. #1
    Registered User
    Join Date
    Sep 2002

    ftoa??? Is there a direct way to convert a float to a string?

    I know how itoa works...

    int x = 100;
    char xstring[4];

    But I need to convert a FLOAT to a string! Can anyone help me?

    double x = 100.10
    char xstring[7];

    I need it to store the decimal place, too.

    Is there a header file that supports this, or does anyone have a function for it?

  2. #2
    Registered User
    Join Date
    Sep 2002
    I think I just figured it out...

    _ecvt Convert double to string of specified length
    _fcvt Convert double to string with specified number of digits following decimal point
    _gcvt Convert double number to string; store string in buffer

    I should use _gcvt, right?

    If so, how can I get it to work right:


    Value to be converted


    Number of significant digits stored


    Storage location for result

    I want digits to store whatever is stored in the floating point version... if I put in 1024, will it store 1024 characters even if they don't have a value?
    Last edited by Trauts; 12-13-2002 at 10:19 AM.

  3. #3
    Registered User
    Join Date
    Sep 2002


    too late now oh well

  4. #4
    Registered User
    Join Date
    Mar 2002
    you could also look up use of stringstreams, if you dont' like to use sprintf(). Though I suspect both versions will have difficulty expressing floats or decimals that don't terminate, like pi, or one third, etc. You probably need to decide on a given approximation to the actual float to convert to a string. Once you do that, you could even create your own function, if you want to continue using itoa.

    //I decided to use only use first 4 decimal places;
    float fNum = 1.2345;
    int wholeNum = fNum;//wouldn't hurt to cast it to avoid warning
    int decimalNum = (int) ((fNum - wholeNum) * 10000);
    char wholeNumStr[10];
    char decNumStr[5];
    char decPtStr = ".";
    char numStr[17];
    itoa(wholeNumStr, wholeNum);
    itoa(decNumStr, decimalNum);
    strcpy(numStr, wholeNumStr);
    strcat(numStr, decPtStr);
    strcat(numStr, decNumStr);

    cout << numStr << endl;

    All sorts of options for you.

Popular pages Recent additions subscribe to a feed

Similar Threads

  1. OOP Question DB Access Wrapper Classes
    By digioz in forum C# Programming
    Replies: 2
    Last Post: 09-07-2008, 04:30 PM
  2. Moving Average Question
    By GCNDoug in forum C Programming
    Replies: 4
    Last Post: 04-23-2007, 11:05 PM
  3. Replies: 4
    Last Post: 03-03-2006, 02:11 AM
  4. Multidimensional String
    By Beast() in forum C Programming
    Replies: 14
    Last Post: 07-03-2004, 12:47 AM
  5. Half-life SDK, where are the constants?
    By bennyandthejets in forum Game Programming
    Replies: 29
    Last Post: 08-25-2003, 11:58 AM