2.2 Construct a logical expression to represent each of the following conditions

Question

2.2 Construct a logical expression to represent each of the following conditions:

a. x is between 3 and 15 but not equal to 10. b. x is between 10 and 20 but not odd.

c. y is divisible by 5 but not by 40.

d. str is a lowercase or uppercase letter.

2.3 What is the difference between the following two statements?

if (n > 2) { if (n < 6) System.out.println("Done!"); } else System.out.println("Error");

if (n > 2) { if (n < 6) System.out.println("Done!"); else System.out.println("Error"); }

2.4 What is the difference between the result of the following two statements?

int cents = (int)(100 * price + 0.5);

int cents = (100 * price + 0.5);

Explanation / Answer

2.2 Construct a logical expression to represent each of the following conditions:

a. x is between 3 and 15 but not equal to 10.
   if ((x > 2) && (x < 16) && (x != 10))

b. x is between 10 and 20 but not odd.
   if ((x > 9) && (x < 21) && (x % 2 == 0))

c. y is divisible by 5 but not by 40.
   if ((y % 5 == 0) && (y % 40 != 0))

d. str is a lowercase or uppercase letter.
   if (Character.isUpperCase(str.charAt(0))) // str is uppercase letter

   else // str is lowercase letter

2.3 What is the difference between the following two statements?

if (n > 2)
{
   if (n < 6)
       System.out.println("Done!");
}
else
   System.out.println("Error");

if (n > 2)
{
   if (n < 6)
       System.out.println("Done!");
   else
       System.out.println("Error");
}

First statement: print "Error" when n <= 2, print "Done" when n > 2 and n < 6
Second statement: print "Error" when n > 2 and n >= 6, print "Done" when n < 6

2.4 What is the difference between the result of the following two statements?

int cents = (int)(100 * price + 0.5);

int cents = (100 * price + 0.5);

First statement: explicit cast the result (100 * price + 0.5) to int before assign the value to cents
Seond statement: compilation error int java because (100 * price + 0.5) is not a int, but a float or double. Java will not do implicit conversion

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