Lab counter

Define a class called Counter whose objects count things. An object of this class records a count that is a nonnegative integer. Include methods to set the counter to 0, to increase the count by 1, and to decrease the count by 1. Include an accessor method that returns the current count value and a method that outputs the count to the screen. Write a program to test

Class Definition 3

Do Display 4.7 (3rd, 2nd ed.) or 4.5 (1st ed.). Then use Display 4.8 to call 4.7.




Question
In Display 4.7, if the method setDate has the parameter as setDate(int month, int day, int year), what kind of changes should be made in its body of codes?

Homework 11/16/2007: lab class definition 2

Study Display 4.4 (2nd ed. and 3rd ed.) or Display 4.2 & Display 4.3 (1st ed.)


1. Comment out date.setDate(6, 17, year); by // date.setDate(6, 17, year);
2. At the next line below, add date.readInput();
3. Run the program again. Fix any problems you may encouter along the way.

add System.out.println(date.month) and see what happens.

Why?
ans:
因為原本的程式是將month day ,year設成private，只要將其改成public即可

lab class definition

Study Display 4.1 and then do Self-Test Exercise 1.

Homework 10-26-2007

Do Project 7 of Chap. 3. (2nd ed. & 3rd ed.) or Project 4 (1st ed.) Hint: You don't have to use nested loops.

Write a program to calculate average income by gender based on the following data, where F stands for female and M for male.
F 62,000
M 25,000
F 38,000
F 43,000
M 65,000
M 120,000
F 80,000
M 30,100


You should be able to allow users to type in a whole line such as F 80,000 followed by next line M 30,100. Without any change made to your program, your program should be able to process a new set of data, such as follows:
M 52,000
M 35,000
F 48,000
M 33,000
F 75,000
F 110,000
F 90,000
M 30,100