怎么编译错误

#include <cstdio>
#include <cmath>
using namespace std;
int main(){
    int n,k,len=0;char x[100];
    scanf("%d%d",&n,&k);
    int n1=n;
    while(n){ 
        int r=(abs(k)+n%k)%abs(k);
        n-=r;
        if(r>=10)x[len++]=r-10+'A';
        else x[len++]=r+'0';
        n/=k;
    }
    printf("%d=",n1);
    for(int i=len-1;i>=0;i--)printf("%c",x[i]);
    printf("(base%d)",k);
    return 0;
}