Question at position 1 Consider the following code segment. double firstDouble = 2.5; int firstInt = 30; int secondInt = 5; double secondDouble = firstInt - secondInt / firstDouble + 2.5; What value will be assigned to secondDouble when the code segment is executed?5.012.525.530.5单项选择题
A
5.0
B
12.5
C
25.5
D
30.5

Question

Question at position 1 Consider the following code segment. double firstDouble = 2.5; int firstInt = 30; int secondInt = 5; double secondDouble = firstInt - secondInt / firstDouble + 2.5; What value will be assigned to secondDouble when the code segment is executed?5.012.525.530.5单项选择题

A

5.0

B

12.5

C

25.5

D

30.5

BlackTom AI · Accepted Answer

Operator precedence: division happens before subtraction and addition, and when an int is used with a double in an arithmetic operation, the int is promoted to double so floating-point division is performed.

Step-by-step evaluation with all intermediate steps:
1) Identify the expression: secondDouble = firstInt - secondInt / firstDouble + 2.5
2) Apply precedence: evaluate the division first: secondInt / firstDouble = 5 / 2.5
   - secondInt (int 5) is promoted to double because firstDouble is 2.5 (double).
   - 5.0 / 2.5 = 2.0
3) Substitute that result into the expression: secondDouble = firstInt - 2.0 + 2.5
4) Perform subtraction and addition left-to-right (addition and subtraction have equal precedence and are left-associative):
   - firstInt - 2.0 = 30 - 2.0 = 28.0
   - 28.0 + 2.5 = 30.5
5) The final double value assigned to secondDouble is 30.5.

Why this answer is correct:
- Division is done before subtraction, so we compute 5 / 2.5 = 2.0, not (30 - 5) / 2.5.
- Type promotion ensures floating-point division, so we get 2.0 rather than integer 2 with truncation.
- The remaining operations on doubles yield 30.5, which matches the double target variable.

Why the other choices are incorrect:
- 5.0: would require a completely different grouping or arithmetic (not obtained from any correct grouping here).
- 12.5: matches the incorrect grouping (firstInt - secondInt) / firstDouble + 2.5 → (30-5)/2.5 + 2.5 = 10 + 2.5 = 12.5, which ignores operator precedence.
- 25.5: matches the incorrect grouping firstInt - (secondInt / firstDouble + 2.5) → 30 - (2.0 + 2.5) = 25.5, which again misapplies grouping.

Final confirmation: The correct evaluated value is 30.5, which matches the provided answer.

Question at position 1 Consider the following code segment. double firstDouble = 2.5; int firstInt = 30; int secondInt = 5; double secondDouble = firstInt - secondInt / firstDouble + 2.5; What value will be assigned to secondDouble when the code segment is executed?5.012.525.530.5单项选择题

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