【c++】现有三个函数（1）double Add(double a) (2)double Add(double a,do

【c++】现有三个函数（1）double Add(double a) (2)double Add(double a,do double Double,double! double double int b(double l,double r) { double a; a 有下函数定义：int fun(,double a ,double b) 定义一个函数void f(double a,double b,double& s,double& m)该函数实现将s=a double(a)和（double）a有区别吗? 编一个类,有个方法double area (double a double b double c);求面积用海伦公式,再 C语言,double a=3 double b=3.0 double b=3.00 double *p,a; *p double 型变量a,b,c