C :: Integer / Floating Conversions

I got the following to compile and execute, but I don't understand how this works. Here is the code verbatim:

Code:
// Basic conversions in C
#include <stdio.h>
int main () {
float f1 = 123.125, f2;
int i1, i2 = -150;
char c = 'a';

[Code] .....

Okay, so first we have some variables declared as integers, floats, (and that char what it's doing). On the same lines we have values assigned to some of those variables. At first the "f2" and the "i1" confused me, but I think they're just variables whose type has been declared but have not received a value. So far I think I'm good. Then we get into the routines

I think​ I understand the first one. i1 didn't originally receive a value assigned to it, so when it says f1 = i1, then f1 (123.125) just becomes an integer, simple enough.

Then we get to the next routine and I'm like what dafuq??? So first we have f1 (123.125) being set to i2 (-150). wtf? So does that mean f1 is now going to have the value of -150? Vice versa? How are they becoming equal? Or does it have nothing to do with the values of the variables at all and just the type??? I'm just totally lost.

The output of that line is "-150 assigned to a float produces -150.000000." Which makes perfect sense to me written in plain English, but I don't understand how the C code works ....