send structure via text protocol to network socket

[zio_mangrovia]

In Ansi C std C89 I want to send the following structure using text protocol via TCP network socket

char text[1024];

struct Prot {
   char id[4];
   char type[2];
   int dim;
} dato;

sprintf(text, "%s %s %d", dato.id, dato.type, dato.dim);

I want to use fix dimension every time I send this structure; my doubt is about int data because I know dimension of first 2 field (4 +2) id+type but I don't know how code this data into text to have fixed dimension,
E.g.

"AA BBBB 2"

AA BBBB 1245"

these strings have different dimensions depend of int value of 3rd field.

if I fixed 10 as maximum string length I'll got 4 char for my string but how to code this data into string so that receiver can always read 10 characters and understand all data?