SCJP 1.6版考題 147

Given:
1. public class LineUp{
2.   public static void main(String[] args){
3.     double d = 12.345;
4.     //insert code here
5.   }
6. }
 

Which code fragment, inserted at line 4, produces the output |12.345|?
 A. System.out.printf("|%7d| \n", d);
 B. System.out.printf("|%7f| \n", d);
 C. System.out.printf("|%3.7d| \n", d);
 D. System.out.printf("|%3.7f| \n", d);
 E. System.out.printf("|%7.3d| \n", d);
 F. System.out.printf("|%7.3f| \n", d);

解答

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Ans: F

解說:

 printf是Java在JDK 
  
 1.5提供C時代超級好用的printf格式化輸出，
 %d是對應的輸出是10進位值(decimal)，%f是float
 7.3則是整數7位小數點3位。