Java Puzzlers筆記--Puzzle 3: Long Division 溢出問題
public class LongDivision{
public static void main(String[] args){
final long MICROS_PER_DAY = 24*60*60*1000*1000;
final long MILLIS_PER_DAY = 24*60*60*1000;
System.out.println(MICROS_PER_DAY / MILLIS_PER_DAY);
}
}
Solution:
顯示: 5
因爲 24*60*60*1000*1000的結果是int類型,再把這個結果轉換成long的,但是24*60*60*1000*1000的結果已經溢出,不能用int表示。
TID:
When working with large numbers, watch out for overflow-it's a silent killer.
Correctly:
public class LongDivision{
public static void main(String[] args){
final long MICROS_PER_DAY = 24L*60*60*1000*1000;
final long MILLIS_PER_DAY = 24L*60*60*1000;
System.out.println(MICROS_PER_DAY / MILLIS_PER_DAY);
}
}
public static void main(String[] args){
final long MICROS_PER_DAY = 24*60*60*1000*1000;
final long MILLIS_PER_DAY = 24*60*60*1000;
System.out.println(MICROS_PER_DAY / MILLIS_PER_DAY);
}
}
Solution:
顯示: 5
因爲 24*60*60*1000*1000的結果是int類型,再把這個結果轉換成long的,但是24*60*60*1000*1000的結果已經溢出,不能用int表示。
TID:
When working with large numbers, watch out for overflow-it's a silent killer.
Correctly:
public class LongDivision{
public static void main(String[] args){
final long MICROS_PER_DAY = 24L*60*60*1000*1000;
final long MILLIS_PER_DAY = 24L*60*60*1000;
System.out.println(MICROS_PER_DAY / MILLIS_PER_DAY);
}
}
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