floats

Question

why the result of bellow code is true while logically it seems to be false(cause they're equal)?!
i know that an integer float(no number after decimal point) behave normally in comparisons but the problem starts as we add some numbers after the decimal point. for example:

float a=0.8
if(0.8>a)
printf("true");
else
printf("false");
//output true

Answer 1

Read this....

https://www.sololearn.com/Discuss/2149084/?ref=app

Answer 2

1)

0.8 is double (IEEE754 using 64 bits)

and

float a = 0.8; // IEEE754 using 32 bits

IEEE754 is the most common format used by computers to represent non-integer numbers...

2) They are stored as:

double 0.8: 0x3FE999999999999A
float 0.8: 0x3F4CCCCD

They are different numbers!

3) If we convert them to decimal :

double 0.8 -> 0.80000000000000004441

float 0.8 --> 0.80000001192092895508

>>> float 0.8 > double 0.8

:)