c++中error C2062和error C2062是什么错误，该如何解决？

Question

在写水仙花数的时候，遇到C2062和error C2065，不知道自己哪里错了

#include<iostream>
using namespace std;
int main()
{
    int N;
    cin >> N;

    switch (N/1) 
    {
    case 3:
        for (int i = 100; i < 1000; i++)
        {
            int num = 100;
            int a = num % 10;
            int b = num / 10 % 10,
            int c = num / 100;
            if (num == (a ^ 3 + b ^ 3 + c ^ 3))
            {
                cout << num << endl;
            }
            num++;
        }
        break;

    case 4:
        for (int i = 1000; i < 10000; i++)
        {
            int num = 1000;
            int a = num % 10;
            int b = num / 10 % 10;
            int c = num / 100 % 10;
            int d = num / 1000;
            if (num == (a ^ 3 + b ^ 3 + c ^ 3 + d ^ 3))
            {
                cout << num;
            }
            num++;
        }
        break;

    case 5:
        for (int i = 10000; i < 100000; i++)
        {
            int num = 10000;
            int a = num % 10;
            int b = num / 10 % 10;
            int c = num / 100 % 10;
            int d = num / 1000 % 10;
            int e = num / 10000;
            if (num == (a ^ 3 + b ^ 3 + c ^ 3 + d ^ 3 + e ^ 3))
            {
                cout << num;
            }
            num++;
        }
        break;

    case 6:
        for (int i = 100000; i < 1000000; i++)
        {
            int num = 100000;
            int a = num % 10;
            int b = num / 10 % 10;
            int c = num / 100 % 10;
            int d = num / 1000 % 10;
            int e = num / 10000 % 10;
            int f = num / 100000;
            if (num == (a ^ 3 + b ^ 3 + c ^ 3 + d ^ 3 + e ^ 3 + f ^ 3))
            {
                cout << num;
            }
            num++;
        }
        break;

    case 7:
        for (int i = 1000000; i < 10000000; i++)
        {
            int num = 1000000;
            int a = num % 10;
            int b = num / 10 % 10;
            int c = num / 100 % 10;
            int d = num / 1000 % 10;
            int e = num / 10000 % 10;
            int f = num / 100000 % 10;
            int g = num / 1000000;
            if (num == (a ^ 3 + b ^ 3 + c ^ 3 + d ^ 3 + e ^ 3 + f ^ 3 + g ^ 3))
            {
                cout << num;
            }
            num++;
        }
        break;

    default :
        break;
    }

    return 0;
}

vs给出的错误提示：
error C2062: 意外的类型“int”
error C2062: “c”: 未声明的标识符

Answer 1