C Union and simultaneous assignment to members -

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• floating point numbers not work expected 6 answers

in following code

#include<stdio.h> int main() {     union myunion     {         int intvar;         char charvar;         float floatvar;     };     union myunion localvar;     localvar.intvar = 10;     localvar.charvar = 'a';     localvar.floatvar = 20.2;     printf("%d ", localvar.intvar);     printf("%c ", localvar.charvar);     printf("%f ", localvar.floatvar); } 

i understand union can hold 1 value @ time. when assign char value, int overwritten, n when assign floatvalue, char overwritten. expecting garbage values int , char variables , 20.200000 float variable last value assigned. following output i'm getting on vs express gcc

1101109658 Ü 20.200001 

unable understand why float value changed ?

this has nothing union, , float value not changed.

it doesn't have enough bits represent 20.2 binary float. that's okay, nobody has many bits.

you should read what every computer scientist should know floating-point arithmetic.