个十百千不同，所以可以加入层级判断！
#include<iostream>
#include<string>
using namespace std;
int main()
{
unsigned n;
string out;
cin >> n;
if (n > 0)
{
unsigned a = n % 10;
for (int i = 1; i <= a; ++i)
{
out = out + to_string(i);
}
n = n / 10;
if (n > 0)
{
unsigned b = n % 10;
for (int i = 0; i < b; ++i)
{
out = string("S") + out;
}
}
n = n / 10;
if (n > 0)
{
unsigned c = n % 10;
for (int i = 0; i < c; ++i)
{
out = string("B") + out;
}
}
}
cout << out;
system("pause");
return 0;
}
