In modern computer systems, a byte consists of
1 answer:
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Answer:
Here is the recursive function sumSquares(num) that takes an integer num as parameter and returns the sum of squares of numbers from 1 to num.
def sumSquares(num):
if(num >= 0): # checks if the value of num is less than or equal to 0
if (num==0): #if value of num is 0
return 0 #returns 0 if value of num is 0
else: #if value of num is greater than 0
return sumSquares(num - 1)+ num * num #recursively calls the sumSquares method to return the sum of squares of numbers from 1 to num
else: # if a user enters a negative num
(print("The number if not positive")) #prints this message
exit() # exits after displaying that number if not positive message
#below print statement is used in order to check the working of the function
print(sumSquares(3)) #calls function and passes value 3 for num
Explanation:
The program works as follows:
The function sumSquares(num) that takes an integer num as parameter and returns the sum of squares of numbers from 1 to num
The first if condition checks if value of num is positive. If this condition evaluates to true then the another if statement inside this if statement is executed which checks if the value of num is 0. If this condition evaluates to true then the program returns 0. However if this condition evaluates to false then the else part executes which has the following statement:
return sumSquares(num - 1) + num * num
For example num = 3
so the above recursive statement works as follows:
sumSquares(3-1) + 3 * 3
sumSquares(2) + 9
Note that the sumSquares() method is called again and the value 2 is passed as num. As 2 is greater than 0. So again the recursive statement executes:
sumSquares(2 - 1) + 2 * 2 + 9
sumSquares(1) + 4 + 9
sumSquares(1) + 13
sumSquare() method is called again and the value 1 is passed as num. As 1 is greater than 0. So again the recursive statement executes:
sumSquares(1 - 1) + 1 * 1 + 13
sumSquares(0) + 1 + 13
sumSquares(0) + 14
sumSquare() method is called again and the value 0 is passed as num
As the value of num=0 So the if (num == 0): condition evaluates to true and the statement returns 0 executes which returns 0:
sumSquares(0) + 14
0 + 14
Hence the output is:
14
The screenshot of the program along with its output is attached.
Answer:
Kindly note that, you're to replace "at" with shift 2 as the brainly text editor can't take the symbol
Explanation:
PhoneLookup.java
import java.io.FileReader;
import java.io.IOException;
import java.util.Scanner;
public class PhoneLookup
{
public static void main(String[] args) throws IOException
{
Scanner in = new Scanner(System.in);
System.out.println("Enter the name of the phonebook file: ");
String fileName = in.nextLine();
LookupTable table = new LookupTable();
FileReader reader = new FileReader(fileName);
table.read(new Scanner(reader));
boolean more = true;
while (more)
{
System.out.println("Lookup N)ame, P)hone number, Q)uit?");
String cmd = in.nextLine();
if (cmd.equalsIgnoreCase("Q"))
more = false;
else if (cmd.equalsIgnoreCase("N"))
{
System.out.println("Enter name:");
String n = in.nextLine();
System.out.println("Phone number: " + table.lookup(n));
}
else if (cmd.equalsIgnoreCase("P"))
{
System.out.println("Enter phone number:");
String n = in.nextLine();
System.out.println("Name: " + table.reverseLookup(n));
}
}
}
}
LookupTable.java
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;
/**
A table for lookups and reverse lookups
*/
public class LookupTable
{
private ArrayList<Item> people;
/**
Constructs a LookupTable object.
*/
public LookupTable()
{
people = new ArrayList<Item>();
}
/**
Reads key/value pairs.
"at"param in the scanner for reading the input
*/
public void read(Scanner in)
{
while(in.hasNext()){
String name = in.nextLine();
String number = in.nextLine();
people.add(new Item(name, number));
}
}
/**
Looks up an item in the table.
"at"param k the key to find
"at"return the value with the given key, or null if no
such item was found.
*/
public String lookup(String k)
{
String output = null;
for(Item item: people){
if(k.equals(item.getName())){
output = item.getNumber();
}
}
return output;
}
/**
Looks up an item in the table.
"at"param v the value to find
"at"return the key with the given value, or null if no
such item was found.
*/
public String reverseLookup(String v)
{
String output = null;
for(Item item: people){
if(v.equals(item.getNumber())){
output = item.getName();
}
}
return output;
}
}
Item.java
public class Item {
private String name, number;
public Item(String aName, String aNumber){
name = aName;
number = aNumber;
}
public String getName(){
return name;
}
public String getNumber(){
return number;
}
}
input.txt
Abbott, Amy
408-924-1669
Abeyta, Ric
408-924-2185
Abrams, Arthur
408-924-6120
Abriam-Yago, Kathy
408-924-3159
Accardo, Dan
408-924-2236
Acevedo, Elvira
408-924-5200
Acevedo, Gloria
408-924-6556
Achtenhagen, Stephen
408-924-3522
Kindly check the attached output image below.
