C #: sum of two two-digit numbers

Question

Possible duplicate:
Why is floating point arithmetic in C # odd?

Hey. I have a problem:

43.65+61.11=104.75999999999999

for decimal correctly:

(decimal)43.65+(decimal)61.11=104.76

Why is the result for double incorrect?

Answer 1

This question and its answers provide a wealth of information about it. - Difference between decimal, float and double in .NET?

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Answer 2

: (, "double" ) . , (, "" ), . : http://effbot.org/pyfaq/why-are-floating-point-calculations-so-inaccurate.htm

Google " " .

Answer 3

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, IEEE 43.65 + 61.11 - . ( - Python 2.7 Visual ++) , 104.76. .

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Answer 4

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Answer 5

double . < 1 x/y. , . , .

:)

Answer 6

base-10, -10 . ( int "" "" .)

IEEE-754 .1 .01. , , , , - , .

:

#include <stdio.h>

int main(int argc, char* argv[]) {
    float f, g;
    double d, e;
    long double l, m;

    f=0.1;
    g=f*f;
    d=0.1;
    e=d*d;
    l=0.1;
    m=l*l;
    printf("%40.40f, %40.40f, %40.40Lf\n", g, e, m);
    return 0;
}

$ ./fp
0.0100000007078051567077636718750000000000,
0.0100000000000000019428902930940239457414,
0.0100000000000000011102569059430467124372

0.01, , .

.

Answer 7

? 104.76, :

class Program
{
    static void Main(string[] args)
    {
        double d1 = 43.65;
        double d2 = 61.11;
        double d3 = d1 + d2;
        Console.WriteLine(d3);
        Console.ReadLine();
    }
}

104.76000213623

class Program
{
    static void Main(string[] args)
    {
        float d1 = 43.65f;
        float d2 = 61.11f;
        double d3 = d1 + d2;
        Console.WriteLine(d3);
        Console.ReadLine();
    }
}

Make sure you convert from float to double, which could cause this problem.