Why output is different

Question

main()
{
float x=7.75;
if(x==7.75)
printf("I am right");
else
printf("I am wrong');
}
Output : I am right

main()
{
float x=0.075;
if(x==0.075)
printf("I am right");
else
printf("I am wrong');
}
Output : I am wrong

Note:- If we use double instead of float output is always I am right. So why it's not possible in float.

Answer 1

Floating-point numbers are represented in computer hardware as base 2 (binary) fractions.

Unfortunately, most decimal fractions cannot be represented exactly as binary fractions. A consequence is that, in general, the decimal floating-point numbers you enter are only approximated by the binary floating-point numbers actually stored in the machine.

The problem is easier to understand at first in base 10. Consider the fraction 1/3. You can approximate that as a base 10 fraction:
0.3
or, better,
0.33
or, better,
0.333
and so on. No matter how many digits you’re willing to write down, the result will never be exactly 1/3, but will be an increasingly better approximation of 1/3.

It's actually quite interesting to read more about this, because all programmers will have to face the importance of choosing your correct data types some time.

//I got this from python docs