Please explain this | Sololearn: Learn to code for FREE!

+2

Please explain this

https://www.sololearn.com/post/1065106/?ref=app

c

5/1/2021 5:28:53 PM

Thirt13n

24 Answers

New Answer

+7

0.7 is 7/10 Since 10 is not a power of 2 the internal representation used by most computer systems which is binary floating point cannot represent this number exactly. So what the computer actually stores when you enter float a = 0.7; is: 0.699999988079071044921875 which is just an approximation of 0.7 when comparing that to the double value that is stored for 0.7, which is: 0.6999999999999999555910790149937383830547332763671875 which is just a closer approximation of 0.7 you see that the first one is actually a bit less than the latter and that is why this program outputs Hi. This however does not apply to all numbers. So for example the same code with 0.6: float a = 0.6; if(0.6 > a) { printf("Hi"); } else { printf("Hello"); } will print Hello instead and that is because the closest 32 bit representation of 0.6 just happens to be slightly bigger than 0.6 while the 64 bit representation is actually just slightly smaller than 0.6

+5

Hi everyone , I get answer from who created this question. 0.7 is generally without any declare data type is considered as double precision value And double precision value of 0.7 is greater than float 0.7 that's why the output will come as "Hi".

+5

Thirt13n I agree with your answer. I just wanted to give a more detailed view of why this effect happens so people hopefully understand the general working principle of floating point numbers a bit better.

+4

Oh, sorry, I thought it was Python, but it is C. I need new glasses. 😳

+3

a is equal to 0.7, so the first condition (a > 0.7) evaluates to False. Thus the string "Hello" will be printed.

+3

Thirt13n so here in terms of range the value is taken?

+3

Hey, it is given that a=0.7 and in the code it written as if a>0.7 else return hi so that's why it is hi

+2

Maher Al Dayekh Why float's value is taken as 0.699?

+2

Atul I honestly have no about this, but I think it's about bits or something like that. Hope someone who knows comes and correct me if I'm mistaken. I tried it in C++ like: float a = 0.7f; double b = 0.7; if(a > b) std::cout << "hello"; else std::cout << "hi"; // output : hi

+2

I think so you are right in saying because when we reverse it,it shows false

+2

Maher Al Dayekh you're rightπŸ‘ŒπŸ™‚

+2

Hey Adish Bahirat Read my comment , you will understand ! We are also confused first time πŸ˜€

+2

Dear when same value we compare in < or > it only give false output. That's why the output should "Hello".... ☺

+2

+2

Here u r writing that if 0.7 is more than a output will be hi and else it would be hello

+2

Yes Gvs Charan Gudaru

+1

a is float so it's actual value is 0.69999998 (not exactly sure about it) and 0.7 is considered as a double (means it stays 0.7) So it's now like: if(0.7 > 0.699) printf("Hi"); // which is true

+1

Hey Hape I'm saying that , 0.7 is by default double number , float a=0.7; if(0.7>a) printf("hi"); else printf("Hello"); For this if condition will be evaluates to true because double is greater than float number !

+1

Gvs Charan Gudaru It is if(0.7>a)

+1

0.7 will be in double precision, so the output is Hi, if you want to get Hello as output, typecast like (float)0.7 and compare it.