C++ 代码
#include <iostream>
#include <string>
using namespace std;
int main(){
string ss;
getline(cin,ss);
char s;
cin >> s;
int len = ss.size();
for(int i = 0; i < len; i++ ){
if(ss[i] == s) ss[i] = '#';
}
cout << ss << endl;
return 0;
}