C++ 语言考试练习题_保留字母

#include<iostream>

#include<algorithm>

#include<iomanip>

#include<cmath>

using namespace std;

int main()

{

  string s;

  cin >> s;

  cout << endl;

  int lee = s.size();

  int count = 0;

  for(int i = 0; i < lee; i++){

    if(s[i] >= 'a' && s[i] <= 'z') {s[count] = s[i]; count++;}

    if(s[i] >= 'A' && s[i] <= 'Z') {s[count] = s[i]; count++;}

  }

  for(int i = 0; i < count; i++){

    cout << s[i];

  }

}