c++ - 段错误 |计算阶乘 |超出索引

Question

我在在线 IDE 上解决的许多问题中都遇到了这种段错误，但我无法完全理解这个问题并因此解决它。请帮助我。
我知道它有时会由于堆栈溢出而发生，因此，我应该使用堆内存。但是怎么做呢？
一个例子是这个查找大数阶乘的代码
代码

// calculate factorial of really large numbers

#include<iostream>
using namespace std;
#define MAX 500

int multiply(int arr[], int x, int len)
{
    int carry = 0;
    int i = 0;
    int temp = 0;


 
        for(; i < len; i++)
        {
            // multiply each digit w the number x and store the carry to be added in the next number
            temp = 0;
            temp = x * arr[i] + carry;
            arr[i] = (temp%10);
            carry = temp/10;
        }
    
        // if end carry is also generated, even that has to be accomodated in the ans
        while(carry != 0)   //18    === 8 1
        {
            temp = carry%10;
            carry /= 10;
            arr[i] = temp;
            len++;
        i++;
    }
    // final length of the number is returned so that it can be printed easily
    return len;
}

void factorial(int n)
{
    int arr[MAX];
   

     // The array initially contains 1
        arr[0] = 1;
        int arrLeng = 1;

    // multiply the nth number with n+1 to obtain the factorial
    for(int i = 2; i <=n; i++)
        arrLeng = multiply(arr, i, arrLeng);

    // print the final ans array though in reverse order
    for(int i = arrLeng-1; i >= 0; i--)
        cout<<arr[i];
    cout<<endl;
}

int main()
{
// input the number
int n;
cin>>n;

    // call the main function
    factorial(n);
    return 0;
}
   

Answer 1

arrLeng超过硬编码 MAX 500 的限制。
您应该始终检查索引。它不应超过 MAX 限制。这不是堆栈或堆上的内存分配问题。