编程练习1.3

C++ primer plus 第六章 编程练习1

  #include<iostream>
  #include<cctype>
  #include<string>
int main()
{
    using namespace std;
    char ch;
    cout << "Read until meet @: \n";
    while ((ch=cin.get())!=EOF)
    {
        if(ch == '@')
             break;
        else if (isupper(ch))
                cout << char(tolower(ch));
                     else if(islower(ch))
                            cout <<char(toupper(ch));
                                else if(isdigit(ch))
                                        continue;
                                    else 
                                        cout << ch;

    }
    return 0;

}