段故障：无法访问内存

Question

我正在执行合并排序代码。我写的代码是：

#include<iostream>
using namespace std;

void merge(int *A,int i,int k,int j)
{
    int l1,l2,c,d;
    int B[j - i + 1],ind = 0;
    l1 = k - i + 1; c = i;
    l2 = j - k; d = k + 1;

    while(l1 > 0 && l2 > 0)
    {
        if(A[c] < A[d])
        {
            B[ind] = A[c];
            c++; l1--;
        }
        else
        {
            B[ind] = A[d];
            d++; l2--;
        }
        ind++;
    }
    while(l1 != 0)
    {
        B[ind] = A[c];
        c++; l1--; ind++;
    }
    while(l2 != 0)
    {
        B[ind] = A[d];
        d++; l2--; ind++;
    }
    for(int l = i;l < j - i + 1;l++)
    {
        A[l] = B[l];
    }
}
int mergesort(int *A,int i,int j)
{
    if(i == j)
        return 0;
    int k = (j - i)/2;
    mergesort(A,i,k);
    mergesort(A,k + 1,j);
    merge(A,i,k,j);
    return 0;
}
int main()
{
    int A[] = {1,5,3,4,2,6};
    mergesort(A,0,5);
    for(int i = 0;i < 6;i++)
    {
        cout<<A[i]<<endl;
    }
}

编译器出现以下错误：

Program received signal SIGSEGV, Segmentation fault.
0x0000000008000b34 in mergesort (A=<error reading variable: Cannot access memory at address 
0x7fffff7eeff8>,
i=<error reading variable: Cannot access memory at address 0x7fffff7eeff4>,
j=<error reading variable: Cannot access memory at address 0x7fffff7eeff0>) at inv_count.cpp:42
42      {

如果仅调用mergesort的第一个实例，则程序运行良好。但这给第二次通话带来了错误。有人可以告诉我为什么会这样以及如何解决吗？

Answer 1

您对中点k的计算是错误的，应该是：