Understanding structures

I was trying to compile the code given in a document, which is not compiling,

Here is the code:-

#include<stdio.h>
#include<time.h>
typedef struct
{
int day;
int month;
int year;
}Date;
//struct date Dob;
void printDate(Date d)
{
printf("%d/%d/%d\n",d.day,d.month,d.year);
}

int main()
{
Date d;
void printDate(Date d);
d.day=8;
d.month=1;
d.year=2023;
return 0;
}
this is the error Iam getting:-

printDate.c:24:1: warning: data definition has no type or storage class
   24 | printDate(Date d);
      | ^~~~~~~~~
printDate.c:24:1: warning: type defaults to ‘int’ in declaration of ‘printDate’ [-Wimplicit-int]
printDate.c:24:1: error: conflicting types for ‘printDate’; have ‘int(Date)’
printDate.c:10:6: note: previous definition of ‘printDate’ with type ‘void(Date)’
   10 | void printDate(Date d)
      |      ^~~~~~~~~