Difficulty: Easy
Correct Answer: f[0] = 0.0
Explanation:
Introduction / Context:
This item tests default initialization for primitive array elements in Java. When you allocate an array of a primitive type, each element is set to that type’s default value.
Given Data / Assumptions:
f
is allocated as new float[2]
.f[0]
.
Concept / Approach:
For float
, the default element value is 0.0f
. When converted to String in concatenation, it prints as 0.0
. This differs from reference types, which default to null
, and from unallocated arrays (which would throw on indexing).
Step-by-Step Solution:
Allocate f
→ elements initialized to 0.0f
. Access f[0]
→ value 0.0f
. String concatenation prints “f[0] = 0.0”.
Verification / Alternative check:
Write f[0] = 1.5f;
and re-run; output becomes f[0] = 1.5
. For double[]
, the default is 0.0
as well, shown with double precision.
Why Other Options Are Wrong:
“0” is an int
-looking presentation; Java prints a float/double as “0.0”. The code compiles and runs fine; there is no exception.
Common Pitfalls:
Confusing default array element values with default reference values; mixing up formatting vs. numeric value.
Final Answer:
f[0] = 0.0
Discussion & Comments