C++ 函数

内联函数的定义及使用

  1. #include <iostream>
  3. using namespace std;
  5. // 内联函数
  6. // 内联函数声明前加上关键字inline
  7. // 内联函数占用内存大，但运行速度快
  8. inline double square(double x){
  9.     return x * x;
  10. }
  12. int main() {
  13.     double a = square(5.0);
  14.     cout << "a : " << a << endl;
  15.     return 0;
  16. }

引用变量的定义，共享变量

  1. #include <iostream>
  3. using namespace std;
  5. // 引用变量
  6. // 使用类型标识符，int &指向int的引用,rodents和rats指向相同的值和内存单元
  7. void referenceVariable(){
  8.     int rats;
  9.     //int *rodents = &rats;
  10.     int & rodents = rats;
  11.     rats = 10;
  12.     cout << "rats Value is : " << rats << endl;
  13.     cout << "rats Address is : " << &rats << endl;
  14.     cout << "rats Value is : " << rodents << endl;
  15.     cout << "rats Address is : " << &rodents << endl;
  16.     // rats Value is : 10
  17.     // rats Address is : 0xffffcbc4
  18.     // rats Value is : 10
  19.     // rats Address is : 0xffffcbc4
  20. }
  22. int main() {
  23.     referenceVariable();
  24.     return 0;
  25. }

定义和使用函数模板

  1. #include <iostream>
  3. using namespace std;
  5. // 函数模板的定义
  6. //template <class Any>
  7. template <typename Any>
  8. void Swap(Any &a, Any &b){
  9.     Any temp;
  10.     temp = a;
  11.     a= b;
  12.     b = temp;
  13. }
  15. void useTemSwap(){
  16.     int i = 10;
  17.     int j = 20;
  18.     cout << "i, j =" << i << "," << j << endl;
  19.     Swap(i, j);
  20.     cout << "i, j =" << i << "," << j << endl;
  21.     double n = 5.0;
  22.     double m = 10.0;
  23.     cout << "n, m =" << n << "," << m << endl;
  24.     Swap(n, m);
  25.     cout << "n, m =" << n << "," << m << endl;
  26. }
  28. int main() {
  29.     useTemSwap();
  30.     return 0;
  31. }

模板函数的实例化和具体化：隐式实例化、显示实例化

  1. // 模板实例化
  3. // 隐式实例化
  4. template void Swap<int> (int &, int &);
  6. // 显示实例化
  7. template <> void Swap<int>(int &, int &);
  8. template <> void Swap(int &, int &);