String representations of floating-point numbers must not be compared or inspected.
Noncompliant Code Example (String Comparison)
This noncompliant code example incorrectly compares the decimal string literal generated by 1/10000.0. The string produced is not 0.0001 but rather 1.0E-4.
int i = 1;
String s = Double.valueOf(i / 10000.0).toString();
if (s.equals("0.0001")) {
// ...
}
Compliant Solution (String Comparison)
This compliant solution uses the BigDecimal class to avoid the conversion into scientific notation. It then performs a numeric comparison, which passes as expected.
int i = 1;
BigDecimal d = new BigDecimal(Double.valueOf(i / 10000.0).toString());
if (d.compareTo(new BigDecimal("0.0001")) == 0) {
// ...
}
Risk Assessment
Comparing or inspecting the string representation of floating-point values may have unexpected results.
Rule | Severity | Likelihood | Remediation Cost | Priority | Level |
|---|---|---|---|---|---|
NUM11-J | Low | Likely | Medium | P6 | L2 |
Android Implementation Details
Comparing or inspecting the string representation of floating-point values may have unexpected results on Android.
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