Question

Manipulating structured data

Purpose

This two-part assignment involves manipulating "structured" data, similar to what might be analyzed with a spreadsheet. This first part requires you to develop pseudocode, which allows you to think about the operations needed without having to follow precise C++ syntax. Pseudocode captures the major operations such as initializations, calculations, loops and decisions. Assignment 6 provided a pseudocode example. The second part of this assignment will translate the pseudocode into C++.

The problem

Every week a company generates a text file containing one line per employee. The lines contain the employee's first name, last name, and total minutes spent during the last week using a browser to view external web sites. These three fields are separated by "white space" (blanks and/or tab characters). The current number of employees is stored in the symbolic value NUM_EMPLOYEES.

Develop an algorithm to:

1. Read each of the NUM_EMPLOYEES lines into an array entry with first name, last name and browser minutes fields.
2. Compute and display the average number of minutes viewing external web sites for all employees.
3. Display the first name, last name, and minutes spent viewing external web sites for all employees who exceed more than twice the average.

Unlike C++, pseudocode does not require you to declare variables before they are used. You can just simply state an operation such as:

    read first name, last name and browser minutes into employee[i]

Don't you wish that the C++ compiler was as forgiving with syntax? The pseudocode does not need to be concerned with the C++-specific details of reading from or writing to the console. However you do need to include all the arithmetic and loop conditions needed to perform calculations rather than just say something like "compute the average browser minutes".

Answer 1

The pseudocode is like this:

//this is the function which will perform all tasks in the problem
PERFORM_TASK(filename, NUM_EMPLOYEES){

    create an object of fstream class and open data file,filename

    create a 2D array emp_info[NUM_EMPLOYEES][3] 
    for(i = 1 to NUM_EMPLOYEES){

        read a line from the file and store it in temp variable

        tokenize the temp string with " " as delimeter  and read first name, last name and browser minutes into emp_info[i]
    }

    initialize a variable SUM as 0
    for(j = 1 to NUM_EMPLOYEES){
        SUM += emp_info[i][2]
    }

    AVERAGE = SUM / NUM_EMPLOYEES
    display(AVERAGE)

    for(j = 1 to NUM_EMPLOYEES){
        
        if(emp_info[2] > 2*AVERAGE){
            show first name, last name and minutes spent in viewing external sites
        }
    }
}

C++ program is below:

#include<iostream>
#include<fstream>
#include<string.h>
using namespace std;

//macro to define no of employees in data file
#define NUM_EMPLOYEES 5

int main(){

    string filename = "data.txt";

    //create a fstream object to open files
    fstream data_file;

    //open data file
    data_file.open(filename);

    //check if file is open or not

    //if file is open
    if(data_file.is_open()){

        //creating emp_info array to store info from file to array
        string emp_info[NUM_EMPLOYEES][3];

        //loop over to load data of NUM_EMPLOYEES to emp_info
        for(int i = 0; i < NUM_EMPLOYEES; i++){

            string temp;
            //read a line from the file
            getline(data_file, temp);


            char* new_line = new char[temp.length() + 1];
            for(int i = 0; i < temp.length(); i++){
                new_line[i] = temp[i];
            }
            //tokenizing data with whitespace as delimeter
            //reading the first name
            char* token = strtok(new_line, " ");
            //storing the first name
            emp_info[i][0] = token;

            //reading the last name
            token = strtok(NULL, " ");
            //storing the last name
            emp_info[i][1] = token;

            //reading the minutes of viewing the external websites
            token = strtok(NULL, " ");
            //storing the minutes
            //we are storing minutes laso in string form here
            emp_info[i][2] = token;

        }

        int sum = 0;

        //finding sum of viewing minutes of all employees
        for(int j = 0; j < NUM_EMPLOYEES; j++){
            sum = sum + stoi(emp_info[j][2]);  //converting string to int
        }

        //calculating average
        double average = float(sum) / NUM_EMPLOYEES;

        cout<<"The avergae viewing minutes are "<<average<<endl;



        cout<<"Following are the employees with vuewing minutes more "<<2*average<<":"<<endl;
        //find the employees having viewing minutes more than twice the average
        for(int k = 0; k < NUM_EMPLOYEES; k++){
            if(stoi(emp_info[k][2]) > 2*average){
                cout<<emp_info[k][0]<<"\t"<<emp_info[k][1]<<"\t"<<emp_info[k][2]<<endl;
            }
        }
    }
    //if here is some error in opening file
    else{
        cout<<"Error in opening "<<filename<<endl;
    }


    return 0;
}

data.txt file:

Amit Rawat 100
Ajay Bisht 1500
Bhism rocket 3000
Om sai 600
emily sed 2000

Output:

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