I'm new to programming and just learning the basics. Below I have something to calculate a person's age based on their input using scanf. I don't know if I'm doing something wrong or if codeblocks isn't working. I put in any any number and I get back an answer of -82


Code:
#include <stdio.h>
#include <stdlib.h>
int main()
{
   int age;
   int currentYear;
   int birthYear;


   age = currentYear - birthYear;


   printf("what year is it?\n");
   scanf("%d", &currentYear);
   printf("what year were you born?\n");
   scanf("%d", &birthYear);
   printf("you are %d years old\n", age);


   return 0;
}