Simple c++ question

This is a discussion on Simple c++ question within the C++ Programming forums, part of the General Programming Boards category; I know how to do it with printf, but how do you limit the amount of digits when using cout ...

  1. #1
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    Simple c++ question

    I know how to do it with printf, but how do you limit the amount of digits when using cout with a float.

  2. #2
    Registered User quagsire's Avatar
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    float floatvar = 1.234567;
    cout << setprecision(4) << floatvar; // will output "1.23"

  3. #3
    Seven years? civix's Avatar
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    ...uh...what quagsire said...

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    Actually, there is an addendum to quagsire's post here, at least, where Borland C++Builder 4 & 5 and MSVC++ are concerned.
    Code:
    #include <iostream>
    #include <conio.h>
    #include <iomanip> // for setprecision and fixed  
    
    int main(){
    float floatvar = 10.23456789;
    std::cout << std::setprecision(4) << floatvar << std::endl;
    std::cout << std::fixed << std::setprecision(4) << floatvar << std::endl;
    std::cout << std::setprecision(4) << floatvar << std::endl;
    getch();
    return 0;
    }
    The listed code displays:

    10.23
    10.2346
    10.2346

    Note that 'fixed' determines the number of places that follow the decimal point when used in conjuntion with 'setprecision()' and remains in effect until disabled.

    A handy thing to be aware of.

    P.S. Notice the rounding of the fraction as opposed to truncation.

    -Skipper
    "When the only tool you own is a hammer, every problem begins to resemble a nail." Abraham Maslow

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