错误:'unary *'(有'int')|的无效类型参数。

#include <stdio.h>
int _area(), _vol(), (*fnptr)();// declare the functions and the function pointer here

_area(a,b)
int a, b;
{
    return (a*b); //The return value of _area after parameters are passed to it
}
_vol(fnptr,c) //engaging the function pointer as a parameter
int c;
{
    fnptr = _area(); //initializing the function pointer to function _area
    int k = (*fnptr)(8,9); // error occurs here
    return (k*c);
}
#include <stdio.h>
int _area(), _vol(), (*fnptr