这道题很简单按题目要求就行了

~~https://oi-wiki.org/math/base/~~

code:

#include<cstdio>

int n,a[1005],tot,base;

int main(){
    scanf("%d%d",&n,&base);
    while(n){
        a[++tot]=n%base;
        n/=base;
    }
    for(int i=tot;i>=1;i--){
        printf("%c",a[i]>10?a[i]-10+'A':a[i]+'0');
    }
    return 0;
}