好像没有什么比三元更简单的表达式了吧。。。。

# include <iostream>
int main()
{
    using namespace std;
cout<<"Please enter one of the following choices:";
cout<<"c)carnivore\t"<<"p)paianist"
     <<"t)tree\t"<<"q)game";
char c;
cout<<"please enter  c,p,t or q:";

cin>>c;

while((c!='c')||(c!='p')||(c!='t')||(c!='q')){
switch(c)
{ case 'c' : cout<<"A maple is carnivore\t";
    break;
   case 'p' : cout<<"A maple is paianist\v";
    break;
   case 't' : cout<<"A maple is tree\t";
    break;
   case 'q' : cout<<"A maple is game\v";
    break;
   default : cout<<"please enter a c,p,t or q:";


}
cin>>c;
}
  system("pause");
  return 0;
}

支持8楼和12楼的兄弟
我喜欢`a<b?0:1;这种用法

12楼的少输出一次。。

# include <iostream>
int main()
{using namespace std;
cout<<"Please enter one of the following choices:\n";
cout<<"c)carnivore\t"<<"p)paianist\n"
     <<"t)tree\t"<<"q)game"<<endl;
char ch;
int i;
i=1;
while(i)
    {cout<<"please enter  c,p,t or q:";

cin>>ch;


    switch(ch)
    { case 'c' : cout<<"A maple is carnivore\t";i=0;
    break;
   case 'p' : cout<<"A maple is paianist\v";i=0;
    break;
   case 't' : cout<<"A maple is tree\t";i=0;
    break;
   case 'q' : cout<<"A maple is game\v";i=0;
    break;
   default :;


        }
}
  system("pause");
  return 0;
}

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while(i) //为什么这么写？循环结束的条件是什么呢？

while(i)  构成一个死循环，  结束条件是i=0