Answer.

a)  An algorithm is an unambiguous, step-by-step procedure for performing some tast, which is guaranteed to end after a finite number of steps.

b)  An infinite loop is a loop, such as while loop, that never ends because the condition for exiting the loop never becomes true.

c)  The machine language of a computer is the programming language in which instructions are encoded as binary numbers that can be executed directly by the hardware of the computers. Programs written in other languages must be translated into machine language before they can be executed.

Answer.

             int age;
             int price;
             System.out.print("What is your age? ");
             age = TextIO.getlnInt();
             if ( age < 13 ) {
                 price = 3;
             }
             else if ( age > 64 ) {
                 price = 7;
             }
             else {
                 price = 10;
             }
             System.out.println("Your price is $" + price);

Answer.

            int countE; 
            countE = 0;
            for ( int i = 0; i < str.length(); i++ ) {
                if ( str.charAt(i) == 'e' ) {
                    countE = countE + 1;
                }
            }
            // countE is equal to the number of e's in str

Answer. My answer assumes that the picture is 5o pixels tall, and the y-coordinate at the top is 10. The bottom endpoints of the lines are separated by 10 pixels, and the first bottom endpoint has x-coordinate 10. We need to know the x-coordinate of the point at the top. It is above the fifth bottom endpoint, which will have x-coordinate 10+(5*10), or 60.

       First solution:
       
             for ( int x = 10; x <= 110; x = x + 10 ) {
                 g.drawLine( 60, 10, x, 60 );
             }
             
             
       Second solution:
       
             int x;
             x = 10;
             for (int i = 1; i <= 11; i++ ) {
                 g.drawline( 60, 10, x, 60 );
                 x = x + 10;
             }

Answer. The first time through the loop, c is 6, and c % 2 is zero, so the value of a does not change; b is squared, so its new value is 4; c is divided by 2, so its new value is 3. The first line of output is "1,4,3". The second time through the loop, c % 2 is 1, and the line a = a * b assigns 4 to a; the values of b and c are changed to 16 and 1. The output is "4,16,1". Finally, the third time through the loop, c % 2 is again equal to 1, and the output is computed as "64,256,0". Since c is now 0, the loop ends. (Remember that c / 2 does integer division, discarding the remainder.) The complete output is:

           1,4,3
           4,16,1
           64,256,0

Answer.

           int num;
           while (true) {
               System.out.print("Enter an integer in the range 1 to 10:  ");
               num = TextIO.getlnInt();
               if ( num >= 1 && num <= 10 ) {
                   break;
               }
               System.out.println("That number is not in the specified range.");
           }
           // At this point, num must satisfy num >= 1 and num <= 10

Answer.

             a)    for (int i = 0; i < numbers.length; i++) {
                         System.out.println( numbers[i] );
                   }
                   
                   
             b)    boolean found42; 
                   found42 = false; // Will be set to true if a 42 is found.
                   for  (int i = 0; i < numbers.length; i++) {
                       if ( numbers[i] == 42 ) {
                           found42 = true;  // Got it!
                           break;
                       }
                   }
                   if ( found42 ) {
                        System.out.println("yes");
                   }
                   else {
                        System.out.println("no");
                   }
                   // The break is not strictly necessary, but
                   //   it makes the code more efficient.

Answer. The first line creates a variable named guess that can refer to an array of double values; it does not create an actual array. The second line creates an array that holds 1000 double value and sets guess to refer to that array. After this, the array elements guess[0], guess[1], ..., guess[999] all exist.

Answer. The possible outputs are 3, 4, 5, 6, and 7. The value of 5*Math.random() is between 0 and 5, but always strictly less than 5. When that value is type-case to int, the fractional part of the value is discarded (that is, the number is rounded down to the nearest integers), so the value must be 0, 1, 2, 3, or 4. Finally, 3 is added to the value, giving 3, 4, 5, 6, or 7.

Answer. Style is ignored by the computer, but it is very important for human readers. Good programming style makes it easier for people to read and understand the program. This is helpful when you are writing the program, and it is very important if you want to share the program source code with other people. It will make it easier for them to understand the program. It will make it easier for them (or you) to modify the program in the future.

Some some style rules include: Use indentation to make the structure of the program clear; this makes it easier to understand where control structures begin and end. Use comments to explain the logic of the program, when it is not clear; this helps readers to understand the code without having to decipher all the details. Follow the naming convention for variables (start with lower case letter, and capitalize embedded words; this makes it easier to remember the proper case when you use the variable. Use meaningful variable names; this makes the intent of the code that uses the variables more meaningful to a human reader.