fn main() {
    let x: i32 = 5;
    let addr = &x as *const i32 as usize;
    {
        println!("addr: 0x{:X} x: {}", addr, x);
        let pa = addr as *mut i32;
        unsafe{*pa = 100};
        println!("addr: 0x{:X} x: {}", addr, x);
        let x: i32 = x + 1;
        let addr = &x as *const i32 as usize;
        println!("addr: 0x{:X} x: {}", addr, x);
    }
    println!("addr: 0x{:X} x: {}", addr, x);
}