указатели.(с)

[Miles]

#include <stdio.h>
#include <conio.h>
int main(void)
{
int *a, b;
float *x, y = 3.5;
double *m, n;
printf("a=%p\n b=%p\n x=%p\n y=%p\n m=%p\n n=%p\n",
&a,&b,&x,&y,&m,&n);
printf("Enter b = ");
scanf("%d", &b);
a = &b;
x = &y;
printf("a = %p\tb = %d\n", a, b);
getch();
b -= (int)y;
printf("a = %p\t*a = %d\tb = %d\n", a, *a, b);
getch();
m = (double*)a;
printf("a = %p\tm = %p\n", a, m);
getch();
m = &n;
printf("n = %p\tm = %p\n", &n, m);
getch();
n = 5.5;
(*m)++;
printf("n = %lf\tn = %p\tm = %p\n", n, &n, m);
getch();
*m = (double)*a-n+(double)*x;
printf("m=%p\t*m=%lf\n", m, *m);
getch();
*m -= 1;
printf("n=%lf n=%p m=%p *(m+1)=%lf\n", n, &n, m, *(m+1));
printf("\n*(m+1)=%p\n",*(m+1));
printf("a=%p\n b=%p\n x=%p\n y=%p\n m=%p\n n=%p\n\n",&a,&b,&x,&y,&m,&n);
printf("a=%d\n b=%d\n x=%f\n y=%f\n m=%lf\n n=%lf\n",a,b,x,y,m,n);
getch();
return 0;

почему *(m+1)=0.000000?