这个题目差不多懂了

#include<iostream>

using namespace std;

int main(){

string str = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

char ans[5];

int index = 0;

int n = 2019;

while(n){

int t = n % 26;

n = n / 26;

ans[index] = str[t - 1];

index++;

}

for(int i = index - 1; i >= 0; i--){

cout<<ans[i];

}

return 0;

}