指出这个程序问题何在，好像不能控制！~
#include<iostream>using namespace std;
int main()
{
int L,I;
cin>>I;
if(100>=I>=90)
L=1;
else
if(90>I>=80)
L=2;
else
if(80>I>=70)
L=3;
else
if(70>I>=60)
L=4;
else
if(60>I>=0)
L=5;
else
cout<<"1748"<<endl;
switch(L)
{
case 1:
cout<<"A"<<endl;
break;
case 2:
cout<<"B"<<endl;
break;
case 3:
cout<<"C"<<endl;
break;
case 4:
cout<<"D"<<endl;
break;
case 5:
cout<<"E"<<endl;
break;
default:
cout<<"1314"<<endl;
}
return 0;
}
