进制转换

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
const int maxn=1e5+5;
typedef long long LL;
char n[maxn];
LL sum = 0;
void turn_10_to_k(int n,int k) {//将十进制转化成k进制
        char ans[maxn];
        memset(ans,0,sizeof(ans));
        int flag=0,j=0;
        if(n<0) {
            flag=1;
            n*=(-1);
        }
        while(n!=0) {
            ans[j]=n%k;
            n/=k;
            if(ans[j]>9) ans[j]='A'+(ans[j]-10);
            else ans[j]=ans[j]+'0';
            j++;
        }
        if(flag) cout<<'-';
        for(int i=j-1;i>=0;i--) cout<<ans[i];
        cout<<endl;
}
void turn_k_to_10(char n[],int k) {//将k进制转化成十进制
    int flag=0;
    if(n[0]=='-') flag=1;
    for(int i=flag;i<strlen(n);i++) {
        sum*=k;
        if(n[i]>='A') sum+=(n[i]-'A'+10);
        else sum+=(n[i]-'0');
    }
    if(flag==1) sum *= -1;
    //cout<<sum<<endl;
    return ;
}
int main(){
	int k,m;
	scanf("%d",&k);
	getchar();
	scanf("%s",n);
	scanf("%d",&m);
	turn_k_to_10(n,k);
	turn_10_to_k(sum,m);
	return 0;
}