| it is necessary the parameters should initialize before it pass to ref. |
it is not necessary to initialize parameters before pass to out. |
| It is not necessary to initialize the value of a parameter before returning to the calling method. |
It is necessary to initialize the value of a parameter before returning to the calling method. |
| The passing of value through ref parameter is useful when the called method also need to change the value of passed parameter. |
The declaring of parameter through out parameter is useful when a method return multiple values. |
| When ref keyword is used the data may pass in bi-directional. ref 主要用于双向的数据传递 |
When out keyword is used the data only passed in unidirectional. out主要用于单向的数据传递 |
