Expressions, Variables and Assignments - A Concise and Practical Introduction to Programming Algorithms in Java - page 28

- Edit the former file to add cos 6 and check numerically whether sin 2 6

+

cos 2 6 = 1 or not, recompile the code, etc.

- Copy the file and rename it to implement another simple program that
computes, say, a triangle area, etc.

Then we suggest readers become familiar with input/output (I/O) file redirec-
tions ( < and > symbols in command line) before proceeding to the following
exercises.

1.11.2 First set of exercises

Exercise 1.1 (Time conversion)

Write a program Convert.java that converts a given number of seconds
int seconds; into the format of hours, minutes and seconds. Print this
equivalent number of seconds using a formatting rule like HH:MM:SS.

Exercise 1.2 (Time conversion with user keyboard input)
Modify the previous program to read the number of seconds from the
console. Let us call this program ConvertIO.java . For example, the
program execution will yield the following session:

How many seconds? 4000
4000s=1hour, 6 min and 40 sec

Create an input text file inputsec.txt that contains the line 4000 ,and
run the program by redirecting both input and output to text files:

prompt% java ConvertIO <inputsec.txt
...
prompt% java ConvertIO <inputsec.txt >result.txt

Exercise 1.3 (Time comparison)

Design a program that compares two time durations (in hour/min/sec
format) by first converting them into their respective total number of sec-
onds, and then comparing the two delays using the if (booleanPredicate
) {} conditional. This voluntarily anticipates the next chapter.

Write another program for comparing the two durations but without
converting them into a total number of seconds. Declare two boolean
values Smaller and Bigger both initialized to false . Then compare
the respective hours, and decide whether we need to assign one of these
boolean values to true or not. For hours matching, test the minutes,

{} else