Odd Check Fails for Negative Numbers
ID |
java.odd_check_negative_safe |
Severity |
low |
Remediation Complexity |
trivial |
Remediation Risk |
low |
Remediation Effort |
low |
Resource |
Reliability |
Language |
Java |
Tags |
reliability, suspicious-comparison |
Rationale
The expression x % 2 == 1 only works correctly for positive numbers. In Java, the % operator preserves the sign of the dividend, so -3 % 2 evaluates to -1, not 1. This means the check incorrectly reports negative odd numbers as even.
// Bad - fails for negative numbers
if (x % 2 == 1) {
// x = -3 would not enter here, even though -3 is odd
}Remediation
Use x % 2 != 0 which works correctly for both positive and negative numbers.
// Good - handles negative numbers correctly
if (x % 2 != 0) {
// x = -3 correctly enters here
}