MISRA.LOGIC.POSTFIX

Operand in a logical 'and' or 'or' expression is not a postfix expression.

MISRA-C++ Rule 5-2-1 (required): Each operand of a logical && or || shall be a postfix-expression.

Rationale

The effect of this rule is to require that operands are appropriately parenthesized. Parentheses are important in this situation both for readability of code and for ensuring that the behaviour is as the developer intended.

Exception

Where an expression consists of either a sequence of only logical && or a sequence of only logical ||, extra parentheses are not required.

Example

if ( x == 0 && ishigh )     // Non-compliant
if ( ( x == 0 ) && ishigh ) // Compliant
if ( x || y || z )          // Compliant by exception,
                            // if x, y and z bool
if ( x || y && z )          // Non-compliant
if ( x || ( y && z ) )      // Compliant
if ( x && !y )              // Non-compliant
if ( x && ( !y ) )          // Compliant
if ( is_odd( y ) && x )     // Compliant
if ( ( x > c1 ) && ( y > c2 ) && ( z > c3 ) )     // Compliant -
                                                  // exception
if ( ( x > c1 ) && ( y > c2 ) || ( z > c3 ) )     // Non-compliant
if ( ( x > c1 ) && ( ( y > c2 ) || ( z > c3 ) ) ) // Compliant as
                                                  // extra() used

Note that this rule is a special case of Rule 5—0—2.