Can someone please explain to me that in java why 0.6 is <0.6f and 0.7is> = 0.7f

Question

Can someone please explain to me that in java why

  if(0.6 <= 0.6f ) System.out.printf("true"); else System.out.printf("false"); 

this PRINTS true but

  if(0.7 <= 0.7f ) System.out.printf("true"); else System.out.printf("false"); 

this PRINTS false

Is this related to IEEE 754 standards when a floating-point number is converted to double for comparison?

can someone explain this in detail the exact work?

Answer 1

Of course, it's just a matter of understanding that none of 0.6, 0.6f, 0.7, and 0.7f is an accurate value. They are the closest represented approximations of the corresponding type. The exact values ​​that are stored for these 4 values ​​are:

 0.6f => 0.60000002384185791015625 0.6 => 0.59999999999999997779553950749686919152736663818359375 0.7f => 0.699999988079071044921875 0.7 => 0.6999999999999999555910790149937383830547332763671875 

With this information, he clearly explains why you get results.

To think of it differently, imagine that you have two floating point decimal numbers, one with four precision digits and one with 8 precision digits. Now let's see how 1/3 and 2/3 will be presented:

 1/3, 4dp => 0.3333 1/3, 8dp => 0.33333333 2/3, 4dp => 0.6667 2/3, 8dp => 0.66666667 

Thus, in this case, the value of lower accuracy is less than that of higher accuracy for 1/3, but this changes by 2/3. This is the same for float and double , only in binary format.