java floating point

float myNumber = 3.146;
// Noncompliant. Because of floating point imprecision, this will be false
if (myNumber == 3.146f) {}
// Noncompliant. Because of floating point imprecision, this will be true
if (myNumber != 3.146f) {}
// Noncompliant. Indirect inequality test
if (myNumber < 4 || myNumber > 4) {}

float zeroFloat = 0.0f;
// Noncompliant. Computations may end up with a value close but not equal to zero.
if (zeroFloat == 0) {}

// This will cause an infinite loop!
// Because 0.1 is an infinite binary decimal, the balance will never be exactly 0.
for (double balance = 10; balance != 0; balance -= 0.1) {
    System.out.println(balance);
}

// This will end the loop, but don't expect it to print as our expectation.
for (double balance = 10; balance > 0; balance -= 0.1) {
    System.out.println(balance);
}

// bad!
if(a == b) {}

// solution 1: look not for equality but for whether the value is close enough
if(Math.abs(a - b) < 1e-7) {}

// solution 2: BigDecimal