我已经制作了以下程序来计算Java中使用BigInteger的n个整数的阶乘,但它总是给出1作为结果。错误在哪里?
import java.math.BigInteger;
import java.io.*;
class Factorial
{
public static void main(String args[])
{
try
{
int key;
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
BigInteger result=new BigInteger("1");
//take the quantity of elements for which factorial is to be calculated
int num=Integer.parseInt(br.readLine());
while(num-->0)
{
//input the number for which factorial is to be calculated
key=Integer.parseInt(br.readLine());
while(key>0)
{
System.out.println(key+""+result);
result.multiply(BigInteger.valueOf(key));
key--;
}
//again make the result back to 1 for next key element
result=new BigInteger("1");
}
}catch(Exception e)
{
//do nothing
}
}
}
答案 0 :(得分:2)
BigInteger是不可变的。需要重新分配[BigIteger].mutlipy([BigInteger])
的结果以获得所需的输出,如:
result = result.multiply(BigInteger.valueOf(key));
在while循环中执行操作后应打印结果。看看这个修改过的代码:
key=Integer.parseInt(br.readLine());
while(key>0){
result = result.multiply(BigInteger.valueOf(key));
key--;
}
System.out.println(key+" "+result);