请问为什么程序一运行各种xlocal报错

#define Size 100
#define ok 0
#define error 1
#include<iostream>
#include<fstream>
typedef int Status;
typedef int SElemType;

using namespace std;
typedef struct   //定义顺序栈
{
    int* base;
    int* top;
    int stacksize;
}Sqstack;

Status InitStack(Sqstack& S)//初始化
{
    S.base = new int[Size];
    if (!S.base) exit(OVERFLOW); //存储分配失败
    S.top = S.base;   //初始为空栈
    S.stacksize = Size;
    return ok;
}

Status Push(Sqstack& S, SElemType e)//入栈
{
    if (S.top - S.base == S.stacksize) return error;//栈满
    *S.top++ = e;
    return ok;
}

Status Pop(Sqstack& S, SElemType& e) //出栈
{
    if (S.base == S.top) return error;//栈空
    e = *--S.top;
    return ok;
}

void conversion(int a)
{
    Sqstack S;
    InitStack(S);
    int i, k;
    i = a;
    while ((a/8)!= 0)
    {
        i = a % 8;
        Push(S, i);
    }
    while (S.base != S.top)
    {
        Pop(S, k);
        cout << k;
    }
}

void main()
{
    int a;
    cout << "请输入一个十进制数：";
    cin >> a;
    conversion(a);
}

宏定义放头文件下面，void main 改成 int main(){return 0;}