Problem E: 零起点学算法97——进制转换

#include<stdio.h>
int main(){
    int n,r,a[];
    while(scanf("%d%d",&n,&r)!=EOF){
        int flag=,i=;
        if(n<){
            flag=;
            n=-n;
        }

        do{
            a[i++]=n%r;
            n=n/r;
        }while(n);

        if(flag==)
        printf("-");
        while(i--){
            if(a[i]>){
                printf("%c",'A'+a[i]-);
            }
            else{
                printf("%d",a[i]);
            }
        }
        printf("\n");
    }
    return ;
}