Question

Hello, I need to implement these small things in my C++ code. Thanks.

1- 10 characters student first name, 10 characters middle name, 20 characters last name, 9 characters student ID, 3 characters age, in years (3 digits)

2- Open the input file. Check for successful open. If the open failed, display an error message and return with value 1.

3- Use a pointer array to manage all the created student variables.Assume that there will not be more than 99 input records, so the size of the student variable pointer array will be 100. Use a “global” variable to define the sizeof the pointer array.

4- Initialize each element in the array of pointers to nullptr

Code:

#include

#include

#include

#include

#include

using namespace std;

struct Student

{

string firstName;

char middleName;

string lastName;

char collegeCode;

int locCode;

int seqCode;

int age;

};

struct sort_by_age

{

inline bool operator()(const Student *s1, const Student *s2)

{

return (s1->age < s2->age); // sort according to age of student

}

};

int ageCalc(Student *studs[], Student *&youngest);

int main()

{

vector students; // create vector object to hold students data

ifstream Myfile; // create input file stream object

Myfile.open("a2data.txt"); // open file

if (!Myfile.is_open())

{

cout << "Could not open the file!";

return 0; //terminate

}

vector words; // create vector object to store words from input file

string line;

while (!Myfile.eof())

{

getline(Myfile, line); // readline from input file stream

line.c_str(); // convert string in to char array

int i = 0; // iterator to iterate over line

string word = "";

while (line[i] != '\0')

{

if (line[i] != ' ')

{

word = word + line[i]; // build word with char

i++;

}

else

{

if (word != "")

words.push_back(word); // add word to vector

word = ""; //reset word to empty string

i++; //ignore white space

}

} //end of line

words.push_back(word); // add word to vector

} //end of file

Myfile.close();

int count = 0; // counts the words proceesed from vector object words

string fname = words.at(count); // variable to store first name of student

count++; //move to next element in the vector

while (count < words.size() - 2)

{

Student *s = new Student;

s->firstName = fname;

string mname = words.at(count);

s->middleName = mname[0];

count++;

s->lastName = words.at(count);

if (words.at(count).size() >= 12) // college code + locCode + seq + age

{

if (words.at(count)[1] >= '0' && words.at(count)[1] <= '9') // if second character is a digit

{

// this is the student id field, and there is no middle name

count--; // move one step back for next iteration

s->middleName = ' '; //blank middle name

s->lastName = words.at(count);

}

}

count++;

string id = words.at(count);

count++;

s->collegeCode = id[0];

string loc = "";

loc = loc + id[1];

loc = loc + id[2];

s->locCode = stoi(loc); // convert string to integer

string seq = "";

for (int j = 3; j < 9; j++)

{

seq = seq + id[j];

}

s->seqCode = stoi(seq); //convert string to int

string age = "";

age = age + id[9];

age = age + id[10];

age = age + id[11];

s->age = stoi(age); // convert string to int

fname = id.erase(0, 12); // delete first 12 char from id and assign remaining to fname

students.push_back(s);

}

words.clear();

sort(students.begin(), students.end(), sort_by_age());

cout << setw(15) << left << "Last Name";

cout << setw(15) << left << "Midlle Name";

cout << setw(15) << left << "First Name";

cout << setw(15) << left << "College Code";

cout << setw(12) << left << "Location";

cout << setw(12) << left << "Sequence";

cout << setw(12) << left << "Age" << endl;

cout << "=======================================================================================" << endl;

for (int i = 0; i < students.size(); i++)

{

cout << setw(15) << left << students.at(i)->lastName;

cout << setw(15) << left << students.at(i)->middleName;

cout << setw(20) << left << students.at(i)->firstName;

cout << setw(13) << left << students.at(i)->collegeCode;

cout << setw(10) << left << students.at(i)->locCode;

cout << setw(12) << left << students.at(i)->seqCode;

cout << students.at(i)->age << endl;

}

cout << endl;

int size = students.size();

Student **stud_arr = new Student*[size];

for(int i=0; i

stud_arr[i] = students[i];

Student *youngest = NULL;

int avg_age = ageCalc(stud_arr, youngest);

cout << "Average age is: " << avg_age << endl;

cout << "Youngest student is " << youngest->firstName << " " << youngest->middleName << " " << youngest->lastName << endl;

for(int i=0; i

delete stud_arr[i];

delete []stud_arr;

students.clear();

return 0;

}

int ageCalc(Student *studs[], Student *&youngest)

{

youngest = studs[0];

int i = 0;

int avg_age = 0;

while (studs[i] != NULL)

{

avg_age += studs[i]->age;

if (youngest->age > studs[i]->age)

youngest = studs[i];

i++;

}

return avg_age / i;

}

txt file needed for the program:

https://drive.google.com/file/d/15_CxuGnFdnyIj6zhSC11oSgKEYrosHck/view?usp=sharing

Answer 1

If you have any doubts, please give me comment...

#include <iostream>

#include <string>

#include <fstream>

#include <algorithm>

#include <vector>

#include <iomanip>

using namespace std;

#define nullptr NULL

#define MAX_SIZE 100

struct Student

{

    string firstName;

    char middleName;

    string lastName;

    char collegeCode;

    int locCode;

    int seqCode;

    int age;

};

struct sort_by_age

{

    inline bool operator()(const Student *s1, const Student *s2)

    {

        return (s1->age < s2->age);

    }

};

int ageCalc(Student *studs[], Student *&youngest);

int main()

{

    Student *students[MAX_SIZE] = {nullptr};

    ifstream Myfile;

    Myfile.open("a2data.txt");

    if (!Myfile.is_open())

    {

        cout << "Could not open the file!";

        return 1;

    }

    vector<string> words;

    string line;

    while (!Myfile.eof())

    {

        getline(Myfile, line);

        line.c_str();

        int i = 0;

        string word = "";

        while (line[i] != '\0')

        {

            if (line[i] != ' ')

            {

                word = word + line[i];

                i++;

            }

            else

            {

                if (word != "")

                    words.push_back(word);

                word = "";

                i++;

            }

        }

        words.push_back(word);

    }

    Myfile.close();

    int count = 0;

    string fname = words.at(count);

    count++;

    int n = 0;

    while (count < words.size() - 2)

    {

        Student *s = new Student;

        s->firstName = fname;

        string mname = words.at(count);

        s->middleName = mname[0];

        count++;

        s->lastName = words.at(count);

        if (words.at(count).size() >= 12)

        {

            if (words.at(count)[1] >= '0' && words.at(count)[1] <= '9')

            {

                count--;

                s->middleName = ' ';

                s->lastName = words.at(count);

            }

        }

        count++;

        string id = words.at(count);

        count++;

        s->collegeCode = id[0];

        string loc = "";

        loc = loc + id[1];

        loc = loc + id[2];

        s->locCode = stoi(loc);

        string seq = "";

        for (int j = 3; j < 9; j++)

        {

            seq = seq + id[j];

        }

        s->seqCode = stoi(seq);

        string age = "";

        age = age + id[9];

        age = age + id[10];

        age = age + id[11];

        s->age = stoi(age);

        fname = id.erase(0, 12);

        students[n] = s;

        n++;

    }

    words.clear();

    sort(students, students + n, sort_by_age());

    cout << setw(15) << left << "Last Name";

    cout << setw(15) << left << "Midlle Name";

    cout << setw(15) << left << "First Name";

    cout << setw(15) << left << "College Code";

    cout << setw(12) << left << "Location";

    cout << setw(12) << left << "Sequence";

    cout << setw(12) << left << "Age" << endl;

    cout << "=======================================================================================" << endl;

    for (int i = 0; i < n; i++)

    {

        cout << setw(15) << left << students[i]->lastName;

        cout << setw(15) << left << students[i]->middleName;

        cout << setw(20) << left << students[i]->firstName;

        cout << setw(13) << left << students[i]->collegeCode;

        cout << setw(10) << left << students[i]->locCode;

        cout << setw(12) << left << students[i]->seqCode;

        cout << students[i]->age << endl;

    }

    cout << endl;

    Student *youngest = NULL;

    int avg_age = ageCalc(students, youngest);

    cout << "Average age is: " << avg_age << endl;

    cout << "Youngest student is " << youngest->firstName << " " << youngest->middleName << " " << youngest->lastName << endl;

    return 0;

}

int ageCalc(Student *studs[], Student *&youngest)

{

    youngest = studs[0];

    int i = 0;

    int avg_age = 0;

    while (studs[i] != NULL)

    {

        avg_age += studs[i]->age;

        if (youngest->age > studs[i]->age)

            youngest = studs[i];

        i++;

    }

    return avg_age / i;

}

========= nagarajuanagaraju-Vostro-3550:28092019$ g++ ageCalcv5.cpp -std=C++11 nagarajuanagaraju-Vostro-3550:28092019$ ./a.out Last Name Midlle Name First Name College Code Location ==================================================== Pollidence Richard Lomo Frank Frankson Colin Bowie Barb Carlo Jim Fuller John Browscent Malic Mungbean Hilbert Jackson James HOUD Em JET med mm Sequence Age ========= ========= 782635 912376 234556 833546 876543 123456 23142 333221 785634 323245 Dave Jim Average age is: 35 Youngest student is Richard E Pollidence ulato 255,200090404