十进制转十六进制

#include <iostream>
#include <cstdio>
#include <vector>
#include <queue>
#include <map>
#include <stack>
#include <cstring>
#include <algorithm>
#include <cstdlib>
#define FOR(i,x,n) for(long i=x;i<n;i++)
#define ll long long int
#define INF 0x3f3f3f3f
#define MOD 1000000007
#define MAX_N 50005

using namespace std;

char a[200000000];

int main()
{
    //freopen("input1.txt", "r", stdin);
    //freopen("data.out", "w", stdout);
    ll n;
    int cou=0;
    scanf("%lld",&n);
    if(n==0){
        printf("0");
    }
    while(n!=0){
        int t=n%16;
        if(t>=10){
            a[cou++]=n%16-10+'A';
        }else{
            a[cou++]=n%16-1+'1';
        }
        n/=16;
    }
    for(int i=cou-1;i>=0;i--){
        printf("%c",a[i]);
    }
    //fclose(stdin);
    //fclose(stdout);
    return 0;
}