PAT (Advanced Level) 1027. Colors in Mars (20)

#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;

void pri(int a)
{
    if (a <= 9) printf("%d", a);
    else printf("%c", a-10+‘A‘);
}

void print(int a){
    if (a >= 13) { pri(a/13);  pri(a%13);}
    else { printf("0"); pri(a); }
}
int main()
{
    int r, g, b;
    scanf("%d%d%d", &r, &g, &b);
    printf("#");
    print(r); print(g); print(b);
    printf("\n");
    return 0;
}