- 函数的缺省参数必须从右向左依次定义,即在模型形式参数的右边不能有缺省的形式参数 比如:int fun(int a = 0, int b, int c = 0)
#include<iostream> //using namespace std; int distance(int x1,int y1,int x2=3,int y2=4); int main() { int a = distance(3,4); int b = distance(4,3); int c = distance(3,4,5); int d = distance(3,4,5,6); std::cout<< a <<std::endl; std::cout<< b <<std::endl; std::cout<< c <<std::endl; std::cout<< d <<std::endl; // cout<< c <<endl; // cout<< d <<endl; return 0; } int distance(int x1,int y1,int x2,int y2) { int x,y; x=x2+x1; y=y2+y1; return x*x+y*y; }