For Loop vs. For-Each Loop: Which is More Performant?

Performance Comparison: for Loop vs. for-Each Loop

In the realm of looping constructs, the question of performance often arises, leading to a comparison between for loops and for-each loops.

For Loop vs. For-Each Loop

Consider the following two loops:

for (Object o: objectArrayList) {
    o.DoSomething();
}

for (int i=0; i<objectArrayList.size(); i++) {
    objectArrayList.get(i).DoSomething();
}

Performance Comparison

According to Item 46 of Joshua Bloch's "Effective Java," there is no performance penalty for using the for-each loop. Rather, it may even provide a slight advantage in certain scenarios.

Reason for Performance Improvement

The for-each loop skips the step of computing the limit of the array index multiple times. In the for loop, it is calculated with each iteration. In contrast, the for-each loop performs this calculation only once.

Conclusion

Programmers who strive for efficiency can use either for loops or for-each loops without significant concerns about performance. However, the simplicity and code readability of the for-each loop make it a more desirable choice in most situations.

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