This article contains C programming syntaxes and equations that behave in a strange way.

Logical && and logical ||

When using the logical AND (&&) or the logical OR (||) the expression is evaluated from left to right. Consider the following code.

    i=1;
    j=8;
 if (( i == 0 ) && (( j++ ) > 0 )) {
  ...code...
 }

The statement of the left side of && evaluates to false the rigth side of the statement is never evaluated - and j is never incremented.

or

    i=0;
    j=8;
 if (( i == 0 ) || (( j++ ) > 0 )) {
  ...code...
 }

The statement of the left side of || evaluates to true the rigth side of the statement is never evaluated - and j is never incremented.

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