java我不懂..

不過可以自己寫個絕對值函數

如果a小於0 則 a=a*(-1)

if (a<=0){
a=a*(-1);
System.out.println(a);
}else(a>0){
System.out.println(a);
}

這應該有類似abs之類的函數吧
印象中每個語言幾乎都有

import java.lang.Math.*;


abs(long a)
Returns the absolute value of a long value.

http://java.sun.com/j2se/1.4.2/docs/api/java/lang/Math.html#abs(long)

abs
public static long abs(long a)Returns the absolute value of a long value. If the argument is not negative, the argument is returned. If the argument is negative, the negation of the argument is returned.
Note that if the argument is equal to the value of Long.MIN_VALUE, the most negative representable long value, the result is that same value, which is negative.


Parameters:
a - the argument whose absolute value is to be determined
Returns:
the absolute value of the argument.
See Also:
Long.MIN_VALUE

基本上Sun有提供完整的文件可供參考，下次您可以先搜尋文件看看喔！

哈哈...好手那個圖形好炫啊
還自己弄成印章喔
我也要來合成一個^___^a