答案及解析：[单选题]如需定义一个求圆面积的函数,下列函数定义哪个是正确的?( ) A double Area(double r) { double s; s = 3.14*r*r; return s; } B void

问题：

[单选题]如需定义一个求圆面积的函数,下列函数定义哪个是正确的?( )
A
double Area(double r) { double s; s = 3.14*r*r; return s; }
B
void Area(double r) { double s; s = 3.14*r*r; return s; }
C
double Area( ) { double s; s = 3.14*r*r; return s; }
D
double Area(double r) { Area = 3.14*r*r; }