将整数转换为罗马数字

我要在大约四个小时内进行一次测试，其中一个问题要求我们将用户输入的最大100的整数转换为罗马数字。我认为我的代码非常接近（我找到了我用作指导的youtube视频），但是可惜我的代码根本行不通:(。有人可以发现错误吗？编辑：啊，很抱歉，问题是

I have a test due in about four hours and one of the questions asks us to convert a user-inputed integer up to 100 into a roman numeral. I think my code is very close (I found a youtube video that I sort of used as a guide) but alas my code simply will not work :(. Can anyone spot the errors? Ah sry sry sry, the problem is that when it compiles, it gives no Roman numerals. As in I enter a value and it gives me a blank.

    #include "stdafx.h"
#include <iostream>
#include <string>
    using namespace std;


int main()
{
    string romnum;
    int input;
    int num;
    cout << "Type in an integer: ";
    cin >> input;
    if(( input >= 101) || (input <= 0)) // <-- this is the upper bound
    {
        cout << "\n INVALID INPUT";
    }
    else
    {
        if(input = 100)
        {
            romnum + 'C';

        }
        input %= 100; // gets the remainder after dividing by 100

        if(input <= 10)
        {
            num = (input/10); // now we are dealing with number in 10s place
            if(num == 9)
            {
                romnum += "XC";
            }
            else if(num >= 5)
            {
                romnum += 'L';

                for(int i=0; i < num - 5;i++)
                {
                    romnum += 'X';
                }
            }
            else if(num == 4)
            {
                romnum += "XL";
            }
            else if(num >= 1)
            {
                for(int i=0; i>num; i++)
                {
                    romnum += 'X';
                }
                input %= 10;
            }
            if(num >= 1)
            {
                num = input; //  now we are dealing with number in ones place
                if(num == 9)
                {
                    romnum += "IX";
                }
                else if(num >= 5)
                {
                    romnum += 'V';
                    for(int i=0; i < num - 5; i++)
                    {
                        romnum += 'I';
                    }
                }
                else if(num == 4)
                {
                    romnum += "IV";
                }
                else if(num >= 1)
                {
                    for(int i = 0; i < num; i++)
                    {
                        romnum += 'I';
                    }
                }
        cout << "The Roman Numeral is: " << romnum;

            }
        }



        cout << "The Roman Numeral is: " << romnum;
    }
    int f;
    cin >> f;
    return 0;
}

enter code here