#include <iostream> using namespace std; int sum(int a, int b=20) { int result; result = a + b; return (result); } int main () { // 局部变量声明 int a = 100; int b = 200; int result; // 调用函数来添加值 result = sum(a, b); cout << "Total value is :" << result << endl; // 再次调用函数 result = sum(a); cout << "Total value is :" << result << endl; return 0; }