What is a transistor, and how did the introduction of transistors lead to faster and cheaper computers? What other effects did transistors have on modern technology and society?
What will be an ideal response?
A transistor is a piece of silicon whose conductivity can be turned on and off using an electric current. Since transistors were smaller, cheaper, more reliable, and more energy- efficient than vacuum tubes, they allowed for the production of more powerful yet inexpensive computers.
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Write a program that converts dates from numerical month–day format to alphabetic month–day format. For example, input of 1/31 or 01/31 would produce January 31 as output. The dialogue with the user should be similar to that shown in Programming Project 2. You should define two exception classes, one called MonthException and another called DayException. If the user enters anything other than a legal month number (integers from 1 to 12), your program should throw and catch a MonthException. Similarly, if the user enters anything other than a valid day number (integers from 1 to either 29, 30, or 31, depending on the month), your program should throw and catch a DayException. To keep things simple, assume that February always has 28 days.
The big problem that influences the design of this project is that the numbers entered are ASCII strings and not integers. The processing that needs to be done (check for valid month numbers, check for valid day numbers, and translate from month numbers to month names) is much easier if the month and day are integers, so that is the approach taken in the solution shown here. The first problem is to parse the input to get the one or two ASCII character digits for each of the data items, month and day. The program uses String methods to find the position of the slash character, /, that separates the two, then usees it to obtain the one or two characters before it for the month, and the one or two characters after it for the day. Next it converts the one- or two-character digits to the decimal integers they represent. A relatively “clean” solution is to write a helper method that converts one ASCII digit-character into its integer value, then use the helper method to convert the one- or two-character month and day values to integers. The code to convert an ASCII integer character to a decimal integer value is written as a switch structure. The month must be converted before day because it is used to determine if the day value is valid. Once the month input is converted to a number it is easy to do the remaining processing. The month can be easily checked for validity (only 1 through 12 are valid values), used as an index into a String array to get the month’s name, and used to check the day number for validity (e.g. if the month number is 1, 3, 5, 7, 8, 10, or 12, the day number must be in the range 1 – 31). The switch structure is also a very good choice for the day-check since it is very compact and readable. Organizing the steps to keep month processing separate from day processing allows the try/catch blocks for the two exceptions to be cleanly and clearly separated. So the solution here is organized as follows: • Parse the input string to get the month part and the day part. • Convert the month part to an integer, if possible. • Check the month for validity: convert day number only if month is valid. It is in this block that a MonthException is thrown for any invalid input for month or if the slash character that separates month and day is missing. Note that any 3-character number for day or month is considered invalid. So, while 01/01 is accepted and converted to January 1, 001/01 and 01/001 are flagged as invalid. If month is a valid number, convert day to its integer value and check for validity. It is here that a DayException is thrown for any invalid day input.
(Quicksort) You have previously seen the sorting techniques of the bucket sort and selection sort. We now present the recursive sorting technique called Quicksort. The basic algorithm for a single-subscripted array of values is as follows:
a) Partitioning Step: Take the first element of the unsorted array and determine its final location in the sorted array (i.e., all values to the left of the element in the array are less than the element, and all values to the right of the element in the array are greater than the element). We now have one element in its proper location and two unsorted subarrays. b) Recursive Step: Perform Step 1 on each unsorted subarray. Each time Step 1 is performed on a subarray, another element is placed in its final location of the sorted array, and two unsorted subarrays are created. When a subarray consists of one element, that subarray must be sorted; therefore, that element is in its final location. The basic algorithm seems simple enough, but how do we determine the final position of the first element of each subarray? As an example, consider the following set of values (the element in bold is the partitioning element—it will be placed in its final location in the sorted array): 37 2 6 4 89 8 10 12 68 45 a) Starting from the rightmost element of the array, compare each element with 37 until an element less than 37 is found. Then swap 37 and that element. The first element less than 37 is 12, so 37 and 12 are swapped. The values now reside in the array as follows: 12 2 6 4 89 8 10 37 68 45 Element 12 is in italics to indicate that it was just swapped with 37. b) Starting from the left of the array, but beginning with the element after 12, compare each element with 37 until an element greater than 37 is found. Then swap 37 and that element. The first element greater than 37 is 89, so 37 and 89 are swapped. The values now reside in the array as follows: 12 2 6 4 37 8 10 89 68 45 c) Starting from the right, but beginning with the element before 89, compare each element with 37 until an element less than 37 is found. Then swap 37 and that element. The first element less than 37 is 10, so 37 and 10 are swapped. The values now reside in the array as follows: 12 2 6 4 10 8 37 89 68 45 d) Starting from the left, but beginning with the element after 10, compare each element with 37 until an element greater than 37 is found. Then swap 37 and that element. There are no more elements greater than 37, so when we compare 37 with itself, we know that 37 has been placed in its final location of the sorted array. Once the partition has been applied to the array, there are two unsorted subarrays. The subarray with values less than 37 contains 12, 2, 6, 4, 10 and 8. The subarray with values greater than 37 contains 89, 68 and 45. The sort continues with both subarrays being partitioned in the same manner as the original array. Based on the preceding discussion, write recursive function quickSort to sort a single-sub- scripted integer array. The function should receive as arguments an integer array, a starting sub-script and an ending subscript. Function partition should be called by quickSort to perform the partitioning step.
Uppercase characters are mathematically greater than lowercase characters.
Answer the following statement true (T) or false (F)
The ________ Report is a pre-built report that contains a summary of your computer's overall performance
A) Task Dynamics B) Performance Master C) System Diagnostics D) Services Diagnostic