cin
int count = 0;
int x ;
cout < < "x = ";
cin > > x > > endl; //奇怪，这个地方报错
while (x)
{
count++;
x=x&(x-1);
}
cout < < "count = " < < count < <endl;

[解决办法]
cout < <endl
cin是输入到变量。。。。