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The intent of the expression in this noncompliant code example is to test the least significant bit of x.
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x & 1 == 0 |
Because of operator precedence rules, the expression is parsed asx & as
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x & (1 == 0) |
which evaluates to
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(x & 0) |
and then to 0.
Compliant Solution
In this compliant solution, parentheses are used to ensure the expression evaluates as expected.
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(x & 1) == 0 |
Exceptions
EXP00-EX1: Mathematical expressions that follow algebraic order do not require parentheses. For instance, in the expressionx + y * zexpression
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x + y * z
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the multiplication is performed before the addition by mathematical convention. Consequently, parentheses to enforce this would be redundant.
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x + (y * z) |
Risk Assessment
Mistakes regarding precedence rules may cause an expression to be evaluated in an unintended way. This can lead to unexpected and abnormal program behavior.
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