Try using Joe, here:

	int joe[7] = { 0, 1, 2, 3, 4, 5, 6 };
	for( i = 0; i = 6; i++ )
		printf( "%d\n", joe[i] );

Then:

	printf( "%d", joe[-1] );
	printf( "%d", joe[-100] );
	printf( "%d", joe[7] );
	printf( "%d", joe[7*35] );

See what values you get.


-:-


Also, find out what happens when you don't initialize your array:

	int zippy[7];
	for( i = 0; i = 6; i++ )
		printf( "%d\n", joe[i] );

Then:
	printf( "%d", joe[-1] );
	printf( "%d", joe[-100] );
	printf( "%d", joe[7] );
	printf( "%d", joe[7*35] );


See what values you get.