Exercise 4: Bring in program grades.cpp and grades.txt from the Lab 10 folder. Fill in the code in bold so that the data is prop
erly read from grades.txt. and the desired output to the screen is as follows: OUTPUT TO SCREEN DATAFILE Adara Starr has a(n) 94 average Adara Starr 94 David Starr has a(n) 91 average David Starr 91 Sophia Starr has a(n) 94 average Sophia Starr 94 Maria Starr has a(n) 91 average Maria Starr 91 Danielle DeFino has a(n) 94 average Danielle DeFino 94 Dominic DeFino has a(n) 98 average Dominic DeFino 98 McKenna DeFino has a(n) 92 average McKenna DeFino 92 Taylor McIntire has a(n) 99 average Taylor McIntire 99 Torrie McIntire has a(n) 91 average Torrie McIntire 91 Emily Garrett has a(n) 97 average Emily Garrett 97 Lauren Garrett has a(n) 92 average Lauren Garrett 92 Marlene Starr has a(n) 83 average Marlene Starr 83 Donald DeFino has a(n) 73 average Donald DeFino 73
1 answer:
Answer:
Here is the C++ program:
#include <fstream> //to create, write and read a file
#include <iostream> // to use input output functions
using namespace std; //to access objects like cin cout
const int MAXNAME = 20; //MAXNAME is set to 20 as a constant
int main(){ //start of main() function
ifstream inData; //creates an object of ifstream class
inData.open("grades.txt"); //uses that object to access and opens the text file using open() method
char name[MAXNAME + 1]; // holds the names
float average; //stores the average
inData.get(name,MAXNAME+1); //Extracts names characters from the file and stores them as a c-string until MAXNAME+1 characters have been extracted
while (inData){ //iterates through the file
inData >> average; //reads averages from file using the stream extraction operator
cout << name << " has a(n) " << average << " average." << endl; //prints the names along with their averages
inData.ignore(50,'\n'); //ignores 50 characters and resumes when new line character is reached. It is used to clear characters from input buffer
inData.get(name,MAXNAME+1);} //keeps extracting names from file
return 0; }
Explanation:
The program is well explained in the comments added to each line of the code. The program uses fstream object inData to access the grades.txt file. It gets and extracts the contents of the file using get() method, reads and extracts averages from file using the stream extraction operator. Then program displays the names along with their averages from grades.txt on output screen.
The grades.txt file, program and its output is attached.
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Answer:
I am writing a JAVA and Python program. Let me know if you want the program in some other programming language.
import java.util.Scanner; // class for taking input from user
public class Reverse{ //class to reverse a sentence
public static void main(String[] args) { //start of main() function body
Scanner input = new Scanner(System.in); //create a Scanner class object
System.out.print("Enter a sentence: "); //prompts user to enter a sentence
String sentence = input.nextLine(); // scans and reads input sentence
String[] tokens = sentence.split(" "); // split the sentence into tokens using split() method and a space as delimiter
for (int i = tokens.length - 1; i >= 0; i--) { //loop that iterates through the tokens of the sentence in reverse order
System.out.println(tokens[i]); } } } // print the sentence tokens in reverse order
Explanation:
In JAVA program the user is asked to input a sentence. The sentence is then broken into tokens using split() method. split method returns an array of strings after splitting or breaking the sentence based on the delimiter. Here the delimiter used is space characters. So split() method splits the sentence into tokens based on the space as delimiter to separate the words in the sentence. Next the for loop is used to iterate through the tokens as following:
Suppose the input sentence is "How are you"
After split() method it becomes:
How
are
you
Next the loop has a variable i which initialized to the tokens.length-1. This loop will continue to execute till the value of i remains greater than or equals to 0.
for (int i = tokens.length - 1; i >= 0; i--)
The length of first token i.e you is 3 so the loop executes and prints the word you.
Then at next iteration the value of i is decremented by 1 and now it points at the token are and prints the word are
Next iteration the value of i is again decremented by i and it prints the word How.
This can be achieved in Python as:
def reverse(sentence):
rev_tokens = ' '.join(reversed(sentence.split(' ')))
return rev_tokens
line = input("enter a sentence: ")
print((reverse(line)))
The method reverse takes a sentence as parameter. Then rev_tokens = ' '.join(reversed(sentence.split(' '))) statement first splits the sentence into array of words/tokens using space as a delimiter. Next reversed() method returns the reversed sentence. Next the join() method join the reversed words of the sentence using a space separator ' '.join(). If you want to represent the reversed tokens each in a separate line then change the above statement as follows:
rev_tokens = '\n'.join(reversed(sentence.split(' ')))
Here the join method joins the reversed words separating them with a new line.
Simply input a line of text and call this reverse() method by passing the input line to it.
