这个声明"浮动(*x [20])(*int a)"是什么意思？

Question

我发现了这个奇怪的变量声明

float (*x[20])(*int a); 

它可能意味着什么？
它的目的是什么？

Answer 1

float (*x[20])(*int a)是不正确的.它应该float (*x[20])(int *a)声明x为一个20个指针的数组,该函数接受一个int *类型的参数并返回float.

对于那些想知道使用函数指针数组的人:

typedef double Func(double, double);          // Declare a double (double, double)

Func sum, subtract, mul, divide;              // Function prototypes.
Func *p[] = { sum, subtract, mul, divide };   // Array of function pointers

int main(void)
{
    double result;
    double a, b;
    int option;
    printf("This is a simple calculator to add, subtract, multiply and divideide two integers\n"); 
    printf("Enter two integers: ");
    scanf("%lf %lf", &a, &b);

    printf("Choose an option:\n 1. Add\n 2. Subtract\n 3. Mult\n 4. Divide\n");
    scanf("%d", &option);

    result = p[option - 1](a, b); 
    printf("result = %lf\n", result);
}

double sum(double a, double b) { return a+b; }
double subtract(double a, double b) { return a-b; }
double mul(double a, double b) { return a*b; }
double divide(double a, double b) { return a/b; }

这里讨论如何读取/解密这种复杂声明的详细说明.