function pointer doesn't give expected output

When I run code, function pointer doesn't give expected output

Code:

---

#include <stdio.h>

void foo ( void )
{   
    int a;
        a = 20;
    printf(" a = %d\n", a);
}


int main()
{
       
        void(*fp)(void) = &foo;


        (*fp);


        return 0;
}

---

I am expecting output it should print 20

You need to enable warnings, for example:
-Wall -Werror -Wpedantic -std=c99
main.c:17:5: error: statement with no effect [-Werror=unused-value]
17 | (*fp);

The correct way: fp(); on line 17

Also, the function name is the entry point address, so you can drop the & and * operators:

Code:

---

...
void (*fp)(void) = foo;

fp();
...

---