第2題SampleCode

Given:
1. public class TestString1{
2. public static void main(String[] args){
3. String str = "420";
4. str += 42;
5. System.out.print(str);
6. }
7. }
What is the output?
A. 42
B. 420
C. 462
D. 42042
E. Compilation fails.
F. An exception is thrown at runtime.
答案：D
參考：3-3 文字串接符號


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public class SCJP6002 {
public static void main(String[] args) {
String str = "420";
str += 42;
System.out.print(str);
}
}

ANS:
D. 42042
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My Answers:
Str = str + 42 == ( 420+42) == 42042
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