为什么Java认为从10到99的所有数字的乘积都是0？
以下代码块的输出为0为什么Java认为从10到99的所有数字的乘积都是0？,java,Java,以下代码块的输出为0 public class HelloWorld{ public static void main(String []args){ int product = 1; for (int i = 10; i <= 99; i++) { product *= i; } System.out.println(product); } } 公共类HelloWorld{ 公共静
public class HelloWorld{
public static void main(String []args){
int product = 1;
for (int i = 10; i <= 99; i++) {
product *= i;
}
System.out.println(product);
}
}
公共类HelloWorld{
公共静态void main（字符串[]args）{
int乘积=1；
对于（inti=10；i它看起来像一个
看看这个
BigDecimal product=new BigDecimal(1);
for(int i=10;i<99;i++){
product=product.multiply(new BigDecimal(i));
}
System.out.println(product);
输出不再是int
值。由于溢出，您将得到错误的值
如果溢出，则返回到最小值并从
如果它下溢，它会回到最大值，然后
从那里继续
更多
编辑
让我们按如下方式更改代码
int product = 1;
for (int i = 10; i < 99; i++) {
product *= i;
System.out.println(product);
}
在中间的某个地方，你可以得到<代码> 0 >代码>作为产品。因此，你的整个产品将是0。
就你而言：
for (int i = 10; i < 99; i++) {
if (product < Integer.MAX_VALUE)
System.out.println(product);
product *= i;
}
// System.out.println(product);
System.out.println(-2147483648 * EvenValueOfi); // --> this is the culprit (Credits : Kocko's answer )
O/P :
1
10
110
1320
17160
240240
3603600
57657600
980179200
463356416
213837312
-18221056
-382642176
171806720
-343412736
348028928
110788608
-1414463488
464191488
112459776
-1033633792
-944242688
793247744
-385875968
150994944
838860800
-704643072
402653184
2013265920
-805306368
-1342177280 --> Multiplying this and the current value of `i` will also give -2147483648 (INT overflow)
-2147483648 --> Multiplying this and the current value of `i` will also give -2147483648 (INT overflow)
-2147483648 -> Multiplying this and the current value of 'i' will give 0 (INT overflow)
0
0
0
for（int i=10；i<99；i++）{
if（乘积<整数最大值）
系统输出打印项次（产品）；
产品*=i；
}
//系统输出打印项次（产品）；
System.out.println（-2147483648*EvenValueOfi）；//-->这就是罪魁祸首（信用：Kocko的答案）
O/P:
1.
10
110
1320
17160
240240
3603600
57657600
980179200
463356416
213837312
-18221056
-382642176
171806720
-343412736
348028928
110788608
-1414463488
464191488
112459776
-1033633792
-944242688
793247744
-385875968
150994944
838860800
-704643072
402653184
2013265920
-805306368
-1342177280-->将此值与“i”的当前值相乘也将得到-2147483648（整数溢出）
-2147483648-->将此值与“i”的当前值相乘也将得到-2147483648（整数溢出）
-2147483648->将此值与当前值“i”相乘将得到0（整数溢出）
0
0
0
每次你将i
的当前值乘以你得到的0
作为输出。如果我运行这个代码，我得到的是全部-
1 * 10 = 10
10 * 11 = 110
110 * 12 = 1320
1320 * 13 = 17160
17160 * 14 = 240240
240240 * 15 = 3603600
3603600 * 16 = 57657600
57657600 * 17 = 980179200
980179200 * 18 = 463356416 <- Integer Overflow (17643225600)
463356416 * 19 = 213837312
213837312 * 20 = -18221056
-18221056 * 21 = -382642176
-382642176 * 22 = 171806720
171806720 * 23 = -343412736
-343412736 * 24 = 348028928
348028928 * 25 = 110788608
110788608 * 26 = -1414463488
-1414463488 * 27 = 464191488
464191488 * 28 = 112459776
112459776 * 29 = -1033633792
-1033633792 * 30 = -944242688
-944242688 * 31 = 793247744
793247744 * 32 = -385875968
-385875968 * 33 = 150994944
150994944 * 34 = 838860800
838860800 * 35 = -704643072
-704643072 * 36 = 402653184
402653184 * 37 = 2013265920
2013265920 * 38 = -805306368
-805306368 * 39 = -1342177280
-1342177280 * 40 = -2147483648
-2147483648 * 41 = -2147483648
-2147483648 * 42 = 0 <- produce 0
0 * 43 = 0
1*10=10
10 * 11 = 110
110 * 12 = 1320
1320 * 13 = 17160
17160 * 14 = 240240
240240 * 15 = 3603600
3603600 * 16 = 57657600
57657600 * 17 = 980179200
980179200*18=463356416以下是程序在每个步骤中的操作：
1*10=10
10 * 11 = 110
110 * 12 = 1320
1320 * 13 = 17160
17160 * 14 = 240240
240240 * 15 = 3603600
3603600 * 16 = 57657600
57657600 * 17 = 980179200
980179200 * 18 = 463356416
463356416 * 19 = 213837312
213837312 * 20 = -18221056
-18221056 * 21 = -382642176
-382642176 * 22 = 171806720
171806720 * 23 = -343412736
-343412736 * 24 = 348028928
348028928 * 25 = 110788608
110788608 * 26 = -1414463488
-1414463488 * 27 = 464191488
464191488 * 28 = 112459776
112459776 * 29 = -1033633792
-1033633792 * 30 = -944242688
-944242688 * 31 = 793247744
793247744 * 32 = -385875968
-385875968 * 33 = 150994944
150994944 * 34 = 838860800
838860800 * 35 = -704643072
-704643072 * 36 = 402653184
402653184 * 37 = 2013265920
2013265920 * 38 = -805306368
-805306368 * 39 = -1342177280
-1342177280 * 40 = -2147483648
-2147483648 * 41 = -2147483648
-2147483648 * 42 = 0
0 * 43 = 0
0 * 44 = 0
VVVVVVVVVVVV
VVVVVVVVVVVV
0 * 97 = 0
0 * 98 = 0
请注意，在某些步骤中，乘法的结果是较小的数字（980179200*18=463356416）或不正确的符号（213837312*20=-18221056），这表明存在整数溢出。但零从何而来？请继续阅读
请记住，int
data type，integer，以下是对每个步骤的说明：
运算结果（1）二进制表示（2）结果（3）
---------------- ------------ ----------------------------------------------------------------- ------------
1 * 10 10 1010 10
10 * 11 110 1101110 110
110 * 12 1320 10100101000 1320
1320 * 13 17160 100001100001000 17160
17160 * 14 240240 111010101001110000 240240
240240 * 15 3603600 1101101111110010010000 3603600
3603600 * 16 57657600 11011011111100100100000000 57657600
57657600 * 17 980179200 111010011011000101100100000000 980179200
980179200 * 18 17643225600 100 00011011100111100100001000000000 463356416
463356416 * 19 8803771904 10 00001100101111101110011000000000 213837312
213837312 * 20 4276746240 11111110111010011111100000000000 -18221056
-18221056 * 21 -382642176 11111111111111111111111111111111 11101001001100010101100000000000 -382642176
-382642176 * 22 -8418127872 11111111111111111111111111111110 00001010001111011001000000000000 171806720
171806720 * 23 3951554560 11101011100001111111000000000000 -343412736
-343412736 * 24 -8241905664 11111111111111111111111111111110 00010100101111101000000000000000 348028928
348028928 * 25 8700723200 10 00000110100110101000000000000000 110788608
110788608 * 26 2880503808 10101011101100010000000000000000 -1414463488
-1414463488 * 27 -38190514176 11111111111111111111111111110111 00011011101010110000000000000000 464191488
464191488 * 28 129973
for (int i = 10; i < 99; i++) {
if (product < Integer.MAX_VALUE)
System.out.println(product);
product *= i;
}
// System.out.println(product);
System.out.println(-2147483648 * EvenValueOfi); // --> this is the culprit (Credits : Kocko's answer )
O/P :
1
10
110
1320
17160
240240
3603600
57657600
980179200
463356416
213837312
-18221056
-382642176
171806720
-343412736
348028928
110788608
-1414463488
464191488
112459776
-1033633792
-944242688
793247744
-385875968
150994944
838860800
-704643072
402653184
2013265920
-805306368
-1342177280 --> Multiplying this and the current value of `i` will also give -2147483648 (INT overflow)
-2147483648 --> Multiplying this and the current value of `i` will also give -2147483648 (INT overflow)
-2147483648 -> Multiplying this and the current value of 'i' will give 0 (INT overflow)
0
0
0
1 * 10 = 10
10 * 11 = 110
110 * 12 = 1320
1320 * 13 = 17160
17160 * 14 = 240240
240240 * 15 = 3603600
3603600 * 16 = 57657600
57657600 * 17 = 980179200
980179200 * 18 = 463356416 <- Integer Overflow (17643225600)
463356416 * 19 = 213837312
213837312 * 20 = -18221056
-18221056 * 21 = -382642176
-382642176 * 22 = 171806720
171806720 * 23 = -343412736
-343412736 * 24 = 348028928
348028928 * 25 = 110788608
110788608 * 26 = -1414463488
-1414463488 * 27 = 464191488
464191488 * 28 = 112459776
112459776 * 29 = -1033633792
-1033633792 * 30 = -944242688
-944242688 * 31 = 793247744
793247744 * 32 = -385875968
-385875968 * 33 = 150994944
150994944 * 34 = 838860800
838860800 * 35 = -704643072
-704643072 * 36 = 402653184
402653184 * 37 = 2013265920
2013265920 * 38 = -805306368
-805306368 * 39 = -1342177280
-1342177280 * 40 = -2147483648
-2147483648 * 41 = -2147483648
-2147483648 * 42 = 0 <- produce 0
0 * 43 = 0
980179200 * 18 = 463356416 (should be 17643225600)
17643225600 : 10000011011100111100100001000000000 <-Actual
MAX_Integer : 1111111111111111111111111111111
463356416 : 0011011100111100100001000000000 <- 32 bit Integer
-2147483648 * 42 = 0 (should be -90194313216)
-90194313216: 1010100000000000000000000000000000000 <- Actual
MAX_Integer : 1111111111111111111111111111111
0 : 00000000000000000000000000000000 <- 32 bit Integer
import java.math.BigInteger;
class Ideone {
public static void main (String[] args) throws java.lang.Exception {
System.out.println("Result: " + (-2147483648 * 42));
}
}
import java.math.BigInteger;
class Ideone {
public static void main (String[] args) throws java.lang.Exception {
BigInteger p = BigInteger.valueOf(1);
BigInteger start = BigInteger.valueOf(10);
BigInteger end = BigInteger.valueOf(99);
for(BigInteger i = start; i.compareTo(end) < 0; i = i.add(BigInteger.ONE)){
p = p.multiply(i);
System.out.println("p: " + p);
}
System.out.println("\nProduct: " + p);
}
}
num max2 total
10 2 1
12 4 3
14 2 4
16 16 8
18 2 9
20 4 11
22 2 12
24 8 15
26 2 16
28 4 18
30 2 19
32 32 24
34 2 25
36 4 27
38 2 28
40 8 31
42 2 32
BigInteger product = BigInteger.ONE;
for (long i = 10; i < 99; i++)
product = product.multiply(BigInteger.valueOf(i));
System.out.println(product.toString());