K进制转换C++代码

转自https://blog.youkuaiyun.com/Love_Irelia97/article/details/83870950

#define uLL unsinged long long

string toKbit(uLL num, int k) {
if( num == 0 )
return "0";
// if( k == 10 )
// return to_string(num);

int  i = 0;
char buffer[66];
while( num != 0 ){
int bit = num % k;
if( bit >= 10 ){
buffer[i++] = 'A' + bit - 10;
}else{
buffer[i++] = '0' + bit;
}
// printf("%d", bit);
num /= k;

}
buffer[i] = '\0';

string res(buffer);//相当于string res = buffer;
reverse(res.begin(), res.end());//逆转参数区间内元素次序
return res;
}

 

 

uLL kBit_to_10(const string& num, int k) {
uLL res = 0, p = 1;
for(int i = num.size()-1; i >= 0; --i, p*=k){ int bit;
if( num[i]>='A' && num[i]<='Z' ){
bit = num[i] - 'A' + 10;
}else{
bit = num[i] - '0';
}
res += (p*bit);
}
return res;
}