【发布时间】：2019-03-26 23:14:07
【问题描述】：
我使用无符号长整数格式来计算大阶乘。但是我的代码在某些时候失败了你能看看吗？实际上，它是指数函数泰勒展开的较大代码的一部分，但此时该部分无关紧要。我将不胜感激任何建议。
谢谢
#include <stdio.h>
#include <math.h>
//We need to write a factorial function beforehand, since we
//have factorial in the denominators.
//Remembering that factorials are defined for integers; it is
//possible to define factorials of non-integer numbers using
//Gamma Function but we will omit that.
//We first declare the factorial function as follows:
unsigned long long factorial (int);
//Long long integer format only allows numbers in the order of 10^18 so
//we shall use the sign bit in order to increase our range.
//Now we define it,
unsigned long long
factorial(int n)
{
//Here s is the free parameter which is increased by one in each step and
//pro is the initial product and by setting pro to be 0 we also cover the
//case of zero factorial.
int s = 1;
unsigned long long pro = 1;
if (n < 0)
printf("Factorial is not defined for a negative number \n");
else {
while (n >= s) {
printf("%d \n", s);
pro *= s;
s++;
printf("%llu \n", pro);
}
return pro;
}
}
int main ()
{
int x[12] = { 1, 5, 10, 15, 20, 100, -1, -5, -10, -20, -50, -100};
//Here an array named "calc" is defined to store
//the values of x.
unsigned long long k = factorial(25);
printf("%llu \n", k);
//int k;
////The upper index controls the accuracy of the Taylor Series, so
////it is suitable to make it an adjustable parameter.
//int p = 500;
//for ( k = 0; k < p; k++);
}
【问题讨论】：
-
20！现在正在成为一件事。 :) 因为它正好处于溢出 64 位整数的极限。