Fundamental Data Types - Java Concepts - page 238

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΢΢Exercise R4.11. True or false? ( x is an int and s is a String )

a. Integer.parseInt(ÐÑ + x) is the same as x

b. ÐÑ + Integer.parseInt(s) is the same as s

c. s.substring(0, s.length()) is the same as s

΢΢Exercise R4.12. How do you get the first character of a string? The last
character? How do you remove the first character? The last character?

΢΢΢Exercise R4.13. How do you get the last digit of an integer? The first
digit? That is, if n is 23456 , how do you find out that the first digit is 2
and the last digit is 6 ? Do not convert the number to a string. Hint: %,
Math.log .

΢΢Exercise R4.14. This chapter contains several recommendations regarding
variables and constants that make programs easier to read and maintain.
Summarize these recommendations.

΢΢΢Exercise R4.15. What is a final variable? Can you define a final
variable without supplying its value? (Try it out.)

΢ Exercise R4.16. What are the values of the following expressions? In each
line, assume that

double x = 2.5;
double y = -1.5;
int m = 18;
int n = 4;
String s = "Hello";
String t = "World";

a. x + n * y - (x + n) * y

b. m / n + m % n

c. 5 * x - n / 5

d. Math.sqrt(Math.sqrt(n))

e. (int) Math.round(x)