编程菜鸟的日记-初学尝试编程-C++ Primer Plus 第6章编程练习1

#include <iostream>
#include <cctype>
using namespace std;
int main()
{
 char ch;
 while((ch=cin.get())!='@')
 {
  if(isdigit(ch))
   continue;
  else if(islower(ch))
   ch-='z'-'Z';
  else if(isupper(ch))
   ch+='z'-'Z';
  cout<<ch;
 }
 system("pause");
 return 0;
}