I wrote a program which i suppose should print true , Instead its giving false as out put.
public class Test {
public static void main(String[] args) {
double i = 0.0 / 0.0;
System.out.println(i - i == 0);
}
}
Can some one explain me why it is behaving so .
It is because i = 0.0 / 0.0 is equal to NaN, so NaN neither equal to 0 nor to it self (Nan)
This is because :
public class TestClass {
public static void main(String[] args) {
double i = 0.0 / 0.0;
System.out.println(i-i); //NaN
System.out.println(i - i == 0);//false
}
}
NaN, standing for not a number, is a numeric data type value representing an undefined or unrepresentable value, especially in floating-point calculations.
double i = 0.0 / 0.0; // this assigned i=NaN
"NaN" stands for "not a number". "Nan" is produced if a floating point operation has some input parameters that cause the operation to produce some undefined result. For example, 0.0 divided by 0.0 is arithmetically undefined. Taking the square root of a negative number is also undefined.
when you compare
System.out.println(i - i == 0); // it do Nan-Nan which is NaN
It try to compare
NaN to 0 which is false
double i = 0.0 / 0.0;
It will evaluate to NaN
And i - i will be NaN - NaN Which is again NaN i.e. != 0
What were you expecting? 0.0 / 0.0 is an indeterminate form, which is mapped with a special value according to floating format which is NaN.
It's a special value because it's destructive, it propagates through each successive arithmetic operation, and that's good because it helps diagnosing problems with operations.
Indeed that's the case 0.0 / 0.0 = NaN and NaN - whatever = NaN (so (0.0/0.0)-5.0 yields NaN too).
