Getting wrong int with arrays

Question

So, My problem here is that I am getting the wrong int from this array and I dont know why. Notice that: pacients.birth = 09/07/1997 in this case.

Using GDB, thats what I have:

Breakpoint 1, ident () at fm.c:72
72      int last = strlen(pacients.birth);
(gdb) n
74      int unidade = pacients.birth[last-1] - '0';
(gdb) n
75      int dezena = pacients.birth[last-2] - '0';
(gdb) p last
$1 = 10
(gdb) p unidade
$2 = 7
(gdb) p dezena
$3 = 1210253312
(gdb) 

Notice that $1 and $2 are correct, but $3 Im getting garbage here...

Answer 1

Looks like I was able to fiz this problem by initiallizing the int`s before, just dont know why yet.

Like this:

int unidade = 0;
int dezena = 0;