C++作用域

#include <iostream>
using namespace std;
int main(int argc, char *argv[])
{
	for(int i = 0; i < 3; ++i)
	{
		cout << "[FOR_1]:" << i << endl;
		for(int i = 0; i < 3; ++i)
		{
			cout << "---------" 
				 << "[FOR_2]:" << i << endl;

			cout << "---------"
				 << "---------";
				 
			for(int i = 0; i < 3; ++i)
			{
				cout << "[FOR_3]:" << i << "  ";		
			}
			
			cout << endl;		
		}
	}
	return 0;
}

运行结果：