Seemingly random value for variable defined in switch block

In C, you can define a variable at the beginning of any block.

For example, the following is correct (although setting i to 5 is weird):

    int i = 5;

    for (i=0; i<1; i++) {
        int j = 1;
        printf("Value FOR: %d\n", j);

    }

Strangely, when doing this in a switch, the value of j seems random.

    int i = 5;

    switch (i)
    {
        int j = 1;
    default:
        printf("Value SWITCH: %d\n", j);
        break;
    }

The piece of code above prints the following on my machine: Value SWITCH: 8 (while it should be Value SWITCH: 1)

Any idea why?

Could it be because in default block, it is actually not instantiated and it reads in random memory?

FYI: I am using gcc version 4.6.1 on Windows, if that matters.