Strange behaviour of two successive printf() calls in C

I was playing with C; check this out:

#include <stdio.h>
#include <stdlib.h>

void main() {
    printf("%d\n", 1.5);
    printf("%f", 0);
}

I expected the output:

0
0.000000

but it prints:

0
1.500000

Did the first printf() pass the 1.5 to second printf()?

PS: I'm aware of ( %d for ints, %f for floats ). As I mentioned, I was just messing with the code.

PS2: I'm using DevC++ & Code::Blocks.