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Do not use a semicolon on the same line as after an if, for, or while statement condition because this it typically indicates programmer error and can result in unexpected behavior.

Noncompliant Code Example

In this noncompliant code example, a semicolon is used on the same line as immediately following an if statement. condition:

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

The statements in the apparent body of the if statement are always evaluated regardless of the result of the condition expression.

Compliant Solution

It is likely, in this example, that the semicolon was accidentally inserted.This compliant solution eliminates the semicolon and ensures that the body of the if statement is executed only when the condition expression is true:

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

Applicability

Placing a semicolon immediately following an if, for, or while condition may result in unexpected behavior.

Automated Detection

Related Guidelines

ISO/IEC TR 24772 "KOA Likely Incorrect Expressions"

MITRE CWE: CWE-480, "Use of Incorrect Operator"

Bibliography

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Image Added Image Added Image Added omission and addition"EXP14-C. Beware of integer promotion when performing bitwise operations on integer types smaller than int      03. Expressions (EXP)      EXP16-C. Do not compare function pointers to constant values