C function isn't working - c

Question

I am writing a function Calculate_age_when_Trump_elected(int year_born) to return a result and assign a value to age_when_Trump_elected.
The result should be the YEAR_TRUMP_ELECTED minus the year of Trump was born but currently it just shows the input that the user enters.
"terminal_user_input.c" is just a file for functions read_string and read_integer.
#include <stdio.h>
#include <ctype.h>
#include <stdbool.h>
#include "terminal_user_input.c"
#define YEAR_TRUMP_ELECTED 2016
// A very basic read boolean function
bool read_boolean(const char* prompt)
{
my_string answer;
bool result;
answer = read_string(prompt);
answer.str[0] = (char) tolower(answer.str[0]);
switch (answer.str[0]) {
case 'n':
result = false;
break;
case 'x':
result = false;
break;
default:
result = true;
}
return result;
}
int Calculate_age_when_Trump_elected(int year_born)
{
int result;
result = YEAR_TRUMP_ELECTED - year_born;
return 0;
}
int main()
{
my_string name;
int age_when_Trump_elected;
int year_born;
bool brexiter;
name = read_string("What is your name? ");
year_born = read_integer("When you were born? ");
age_when_Trump_elected = Calculate_age_when_Trump_elected(year_born);
printf("You were %d years old when Trump was elected\n",year_born);
brexiter = read_boolean("Are u a Brexit support? ");
if (brexiter == true)
{
printf("%s is a Brexit supporter\n",name.str);
}
else
{
printf("%s isn't a Brexit supporter\n",name.str);
}
read_string("Type 'exit' to continue ");
return 0;
}

Answer 1

Look at Calculate_age_when_Trump_elected. It will always return 0. You should return the result variable instead.