Introduction
，，hashCode，displayTodoList ，displayOrdered ，addTask ，removeTask ，
alterTaskPriority
Requirement
1.0 System Analysis
The class diagrams for this project is as following:
2.0 System Design
Task class used to store a task information. It’s implements the Comparable Interface and rewrite the equals and hashCode function.
This program give each task an id. We access the task by id and do the operation.
Todo class provide the following operations:
Function displayTodoList display a list of all tasks on screen.
Function displayOrdered display a list of all tasks orderd by priority and due today on screen.
Function addTask add a task to the list.
Function removeTask remove an item from the list.
Function alterTaskPriority alter the priority of a task.
Function alterTaskDue alter the due of a task.
Function readFromFile read a list of tasks from a text file and load the data into field taskList.
Function writeIntoFile storage all the tasks into a file.
3.0 Test Plan
Case1: display all the tasks
1| read the chapter1 of algorithm| 0| todo
2| clean the table| 2| done
3| make lunch| 1| todo
Case2: display all the tasks ordered by priority
2| clean the table| 2| done
3| make lunch| 1| todo
1| read the chapter1 of algorithm| 0| todo
Case3: add a task : clean the floor
1| clean the table| 2| done
2| make lunch| 1| todo
3| read the chapter1 of algorithm| 0| todo
4| clean the floor| 0| todo
Case4: remove a task, id: 2
1| clean the table| 2| done
2| read the chapter1 of algorithm| 0| todo
3| clean the floor| 0| todo
Case5: alter a task’s priority, id: 3 priority: 4
1| clean the table| 2| done
2| read the chapter1 of algorithm| 0| todo
3| clean the floor| 4| todo
Case6: alter a task’s due, id: 3 due done
1| clean the table| 2| done
2| read the chapter1 of algorithm| 0| todo
3| clean the floor| 4| done