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Do not use the assignment operator in the outermost expression of an if or switch statement or a looping statement (while, do, or for) because this typically indicates programmer error and can result in unexpected behavior.

Noncompliant Code Example

In this noncompliant code example, an assignment expression is the outermost expression in an if statement.

...

While the intent of the code could be to assign b to a and test the value of the result for equality to zero, it is frequently a case of the programmer mistakenly using the assignment operator = instead of the equals operator ==.

Compliant Solution

When the assignment of b to a is unintended, this conditional block is now executed when a is equal to b.

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Code Block
bgColor#ccccff
public void exampleFunction(Object a, Object b){

  a = b;
  if (a == 0) {
    /* ... */
  }

}

Risk Assessment

Errors of omission can result in unintended program flow.

Recommendation

Severity

Likelihood

Remediation Cost

Priority

Level

EXP04-J

low

likely

medium

P6

L2

Related Guidelines

CERT C Secure Coding Standard

EXP18-C. Do not perform assignments in selection statements

CERT C++ Secure Coding Standard

EXP19-CPP. Do not perform assignments in conditional expressions

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[ISO/IEC TR 24772:2010

http://www.aitcnet.org/isai/]

"Likely Incorrect Expression [java:KOA]"

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MITRE CWE

CWE ID 480, "Use of Incorrect Operator"

Bibliography

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[java:[Hatton 1995

AA. Bibliography#Hatton 95]]

Section 2.7.2, "Errors of omission and addition"

]]></ac:plain-text-body></ac:structured-macro>

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