function pointer doesn't give expected output

[vajra11]

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

 #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

[thmm]

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

[flp1969]

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

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

fp();
...