^= 运算符
#include <iostream>
using namespace std;
bool state = 0;
void log()
{
cout << state << endl;
}
void turnOn()
{
state ^= 1 ;//等价于 state = (state ==0)?1:0;
log();
}
int main(int argc, const char * argv[]) {
// insert code here...
int i = 0;
while (i<10) {
turnOn();
i++;
}
return 0;
}