100的阶乘问题
求解，为什么结果为0，什么事溢出，怎么就会溢出，怎么解决？我刚学习C语言，希望多多关照！
[解决办法]
溢出就是开辟的空间已经不够用了，不能够存放你要表示的数了。
int型的数据最大能表示2的16次方减1,100的阶乘都比这个数大了，肯定不能用int来保存了。
你可以搜下大数处理。
[解决办法]
100的阶乘超过了int类型数的最大值，造成数据溢出，所以结果为0
[解决办法]
每次输出a的值看看，像这样：
int a = 1, b = 2;
while (b <= 100)
{
a = a * b;
b++;
printf("%d\n", a);
}
100的阶乘法要用高精度了，即用数组来模拟。
[解决办法]
求100的阶乘有一个比较简单的办法就是将int类型改为double类型
[解决办法]
修改数据类型，扩大范围就行了
[解决办法]
你搜一下 大数阶乘，很多人专门研究这个
[解决办法]
不知道这个算不算答案
#include "stdio.h"
int main()
{
double a=1;
int b=2;
while(b<=100)
{
a=a*b;
b++;
}
printf("%g\n",a);
getchar ();
return 0;
}
[解决办法]
我觉得这样的数据范围肯定是用高精度来计算了，如果楼主需要的话，我可以发代码
[解决办法]
#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
int COMPARE(string number1, string number2) {
int i,j;
int length1 = number1.size();
int length2 = number2.size();
if(number1.size() == 0) number1 = "0";
if(number2.size() == 0) number2 = "0";
j = 0;
for(i = 0; i < length1; ++i) {
if(number1[i] == '0') ++j;
else break;
}
number1 = number1.substr(j);
j = 0;
for(i = 0; i < length2; ++i) {
if(number2[i] == '0') ++j;
else break;
}
number2 = number2.substr(j);
length1 = number1.size();
length2 = number2.size();
if(length1 > length2) {
return 1;
} else if(length1 == length2) {
if(number1.compare(number2) > 0) {
return 1;
} else if(number1.compare(number2) == 0) {
return 0;
} else {
return -1;
}
} else {
return -1;
}
return 0;
}
string PLUS(string number1,string number2) {
int i;
int length1 = number1.size();
int length2 = number2.size();
string result="";
reverse(number1.begin(), number1.end());
reverse(number2.begin(), number2.end());
for(i = 0; i < length1 && i < length2; i++) {
char c = (char)(number1[i] + number2[i] - 48);
result = result + c;
}
while(i < length1) {
result = result + number1[i];
++i;
}
while(i < length2) {
result = result + number2[i];
++i;
}
int carry = 0;
for(i = 0; i < (int)result.size(); ++i) {
int value = result[i] - 48 + carry;
result[i] = (char)(value % 10 + 48);
carry = value / 10;
}
if(carry !=0 ) {
result = result + (char)(carry + 48);
}
for(i = result.size() - 1; i >= 0; i--) {
if(result[i] != '0') break;
}
result = result.substr(0, i + 1);
reverse(result.begin(), result.end());
if(result.length() == 0) result = "0";
return result;
}
string MINUS(string number1,string number2) {
int i;
string result = "";
int length1 = number1.size();
int length2 = number2.size();
if(COMPARE(number2,number1) > 0) {
return "-" + MINUS(number2, number1);
}
reverse(number1.begin(),number1.end());
reverse(number2.begin(),number2.end());
for(i = 0; i < length1 && i < length2; i++) {
char c = number1[i] - number2[i] + 48;
result = result + c;
}
if(i < length1) {
for(; i < length1; i++) {
result = result + number1[i];
}
}
int carry = 0;
for(i = 0; i < (int)result.length(); i++) {
int value = result[i] - 48 + carry;
if(value < 0) {
value = value + 10;
carry = -1;
} else carry = 0;
result[i]=(char)(value + 48);
}
for(i = result.size() - 1; i >= 0; i--) {
if(result[i] != '0')break;
}
result = result.substr(0, i+1);
reverse(result.begin(), result.end());
if(result.length()==0) result = "0";
return result;
}
string MULTIPLY(string number1, string number2) {
int i, j;
int *iresult;
int length1 = number1.size();
int length2 = number2.size();
string result = "";
reverse(number1.begin(), number1.end());
reverse(number2.begin(), number2.end());
iresult = (int*)malloc(sizeof(int) * (length1 + length2 + 1));
memset(iresult, 0, sizeof(int) * (length1 + length2 + 1));
for(i = 0; i < length1; i++) {
for(j = 0; j < length2; j++) {
iresult[i+j] += ((number1[i] - 48) * (number2[j] - 48));
}
}
int carry = 0;
for(i = 0; i < length1 + length2; i++) {
int value = iresult[i] + carry;
iresult[i] = value % 10;
carry = value / 10;
}
for(i = length1 + length2 - 1; i >= 0; i--) {
if(iresult[i] != 0)break;
}
for(; i >= 0; i--) {
result = result + (char)(iresult[i]+48);
}
free(iresult);
if(result == "") result = "0";
return result;
}
string factorial(string n) {
string temp = "1";
string i;
for(i = "1"; COMPARE(i, n) <= 0; i = PLUS(i, "1")) {
temp = MULTIPLY(temp, i);
}
return temp;
}
int main(void) {
cout << factorial("100") << endl;
return 0;
}
