Lab 7: Keyboard Input

Rewrite Display 2.6 using BufferedReader.

You need to import the following packages in the first place.

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

Change

Scanner keyboard= new Scanner(System.in);

into

BufferedReader keyboard= new BufferedReader(new InputStreamReader(System.in));

String inputString = keyboard.readLine();

Note the Main method needs IOException handling as follows:

public static void main (String[] args) throws IOException

Lab 6: Scanner

Do Display 2.6.

What is ASCII?

Homework 3

1. Write a program that can reverse the order of an input string. For example, if you input "ab", it will output "ba". If you input "abcdefg", it should return "gfedcba".



2. Write a program that can print names alternatively. The names are in the format of "First Name + Last Name" or "Last Name, First Name". For example, if you input "Walt Savitch", your program will output "Savitch, Walt". If you input "Savitch, Walt", your program will output "Walt Savitch".

Lab 5: String Processing

Do Project 5 of Chap. 1 on Page 56.

Write a program that starts with a line of text and then outputs that line of text with the first occurrence of "hate" changed to "love". For example, a possible sample output might be

The line of text to be changed is:
I hate you.
I have rephrased that line to read:
I love you.

Hint: You may consider use the methods: indexOf(A_String) and substring(Start, End) in your program.

Lab 4: Java casting

Write a Java program as follows:

Let m=1, n=2;
Print m/n
Print m/ (double)n;
Print (double) m/n;

Lab 3: Java operators

(a) Write a Java program as follows:

Let i=2;
Print i;
Print 2 * (i++);
Print i;

Ans: 2, 4, 3



(b) Write a Java program as follows:

Let i=2;
Print i;
Print 2 * (++i);
Print i;

Ans: 2, 6, 3

Homework 2

1. Suppose you are a landscape architect who charges $5,000 per mile to landscape a highway, and suppose you know the length in feet of the high way you are working on. Write a Java program to calculate the price you charge when the length is 6000 and 4000, respectively.

Hint: There are 5280 feet in a mile.


2. Write a Java program that displays the results of the expressions 15/4, 4/15, 15%4, 4%15. Calculate the values of these expressions manually to verify that the displayed values are correct.


15/4算出來的結果為3.75。
4/15算出來的結果為0.266666666...6，程式用浮點數值只算到小數點第八位，會有誤差而得到的結果為0.26666668。
15%4為15/4的值取餘數，與程式計算結果一樣為3。
4%15為4/15的值取餘數，與程式計算結果一樣為4。