Does C Guarantee Short-Circuit Evaluation for All Types Like Java?

Short Circuit Evaluation in C : A Comparison with Java

In programming, short circuit evaluation is a vital performance optimization technique employed in conditional statements. It involves evaluating the operands in an expression from left to right and ceasing the evaluation as soon as the result is determined.

In Java, utilizing the && operator for short circuiting is a common practice:

if (a != null && a.fun());

This expression leverages short circuit evaluation, where a.fun() is only evaluated if a is not null.

The question arises: Can C replicate this functionality with the following expression?

if (a != 0 && a->fun());

While this expression is syntactically similar, it should be noted that short circuit evaluation in C is not implicitly guaranteed across all types. It is only assured for built-in types like int, bool, and pointers.

For custom types defined by programmers, overloading the && or || operators can disable short circuiting. Thus, overloading these operators is generally discouraged for performance reasons.

In summary, while C supports short circuit evaluation for built-in types, it does not unconditionally guarantee it for user-defined types. Programmers should consider these limitations when designing code that relies on short circuiting for optimal performance.

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