阅读下列程序，写出运行结果:
#include<iostream>
using namespace std;
int main()
{
int a = 0, b = 1;
switch( a )
{
case 0:
switch( b )
{
case 0 : cout<<"a="<<a<<" b="<<b<<endl; break;
case 1 : cout<<"a="<<a<<" b="<<b<<endl; break;
}
case 1:
a++; b++; cout<<"a="<<a<<" b="<<b<<endl;
}
} 
a= 0 b= 1
a= 1 b= 2