两种方法 都供上了。递归 和 用栈。

#include <iostream>
#include <string>
#include <stack>

using namespace std;

char charr[26] = { 'A','B','C','D','E','F','G','H','I','J'
,'K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'
};

void jinzhuan(int X,int M) {
	if (X == 0) {
		return;// 等于 0 进行返回
	}
	jinzhuan(X / M, M);
	int temp = X % M;

	if (temp < 10) {
		cout << temp;
	}
	else {
		cout << charr[temp - 10];
	}
	
}



int main(void) {
	int X, M;
	cin >> X >> M;
	/*stack<int> s;

	while (X != 0) {
		s.push(X % M);
		X /= M;
	}
	while (!s.empty()) {
		int temp = s.top();
		if (temp < 10) {
			cout << temp;
		}
		else {
			cout << charr[temp - 10];
		} 
		s.pop();
	}*/
	jinzhuan(X, M);

	return 0;
}