Why does this program print "Solo" and not "Learn"

Question

float a=0.7;
if(a<0.7)
cout<<"Solo"<<endl;
else
cout<<"Learn"<<endl;

Answer 1

Floating point precision is not accurate, never compare equality directly with them.
0.7 as a floating point could be 0.6999999..
Hence, is less than 0.7.

If you want to compare floating points try to remove the possible error gap.

Something like:

if (a < 0.7 - 0.000001)

Should do.

Answer 2

I agree with @James if the case was

if (a <= 0.7){

cout << " Solo"
// would print
}

Answer 3

@Shashank

that is true!

so if I say

0.2 > 0.7

it is false

The compiler checks

and when true or false is known this happens

if( 0.2 < 0.7){

// true
} else {

//false

}

Answer 4

@Shashank

when you said

0.7

was greater

You knew there was only one answer

The compiler is the same

if "if" is CORRECT ONLY it code inside the if is executed

if "if" is WRONG ONLY the code in else is executed

Answer 5

I can provide an example.

It will be completed shortly.

Answer 6

Another example

- enter a float

ex: 0.4

https://code.sololearn.com/cWKuIrmztc6s/?ref=app

Answer 7

That is because only one case is seleted in the if/else case not both.

Answer 8

Here is an example

https://code.sololearn.com/cT6I5FfHq1Ck/?ref=app

Answer 9

@Shashank

Which is greater?

0.2 or 0.7

Answer 10

It is because of precision error. Like when you store 0.7 as float, it will be stored in binary form in the memory with extra padding of bits e.g. 0.69999999

and when you compare it with exact 0.7, the result is true bcoz 0.69999999 is less than 0.7 Hence, "Solo" is printed.

If you compare it with 0.7f "Learn" will print bcoz this 0.7f too will be stored as 0.69999999

Answer 11

you took int a = 0.7;
a will be 0 because int never takes floating point.

hence 0 < 0.7 will be true

if you give int a = 1.7;
a will be 1
if .... int a = 5.0;
a will be 5

Answer 12

Floating point values are not precise.

Answer 13

@Ray this article would help http://www.geeksforgeeks.org/floating-point-representation-basics/

Answer 14

@manual: 0.7 obviously!

Answer 15

If the if statement is true, the else is not printed.

Answer 16

kartikey: i tried on all data types!
Why isn't the else part getting executed!
Why and how is a decimal value treated to be less than itself?

Answer 17

@Manual: Sry I didn't get you!
Would you mind being more specific and explain with a reason for your solution!
Thank you

Answer 18

from Your Code You didnt specify What it will print when you input value of a =0.7 You only inputed if (a <0.7)
you will see if you put lower value like 0.6 it will print 'learn'

why dont you give it a less than nd Equal to Value

Answer 19

Ok then try the same program by replacing ""a=0.7"" by ""a=0.2"" and ""if(a<0.7)"" by ""if(a<0.2)

then you'll get learn as output.
how's that possible

Answer 20

@Restoring_faith: I appreciate your answer!
but that problem of not printing the else part prevails even after changing the data type to int