There’s a macro UINT32_MAX defined in stdint.h which you can use #include <stdint.h> uint32_t max = UINT32_MAX; More about the relevant header <stdint.h>: http://pubs.opengroup.org/onlinepubs/009695299/basedefs/stdint.h.html
Int(arc4random_uniform(26)) does two things, one it eliminates the negative results from your current method and second should correctly creat an Int from the result.
uint32_t is standard, uint32 is not. That is, if you include <inttypes.h> or <stdint.h>, you will get a definition of uint32_t. uint32 is a typedef in some local code base, but you should not expect it to exist unless you define it yourself. And defining it yourself is a bad idea.