Question

Am I getting this error because i declared 'n' as an int, and then asking it to make it a double?

This is the coude:

#include "stdafx.h"

#include <iostream>

#include <fstream>

#include <string>

#include <algorithm>

#include <vector>

using namespace std;

void sort(double grades[], int size);

char calGrade(double);

int main()

{

   int n;

   double avg, sum = 0;;

   string in_file, out_file;

   cout << "Please enter the name of the input file: ";

   cin >> in_file;

   cout << "Please enter the name of the output file: ";

   cin >> out_file;

   ofstream out;

   out.open(out_file.c_str());

   double *scores = new double[n];

   ifstream in;

   in.open(in_file.c_str());

   if (in.fail())

   {

       cout << "Unable to open file" << endl;

       exit(0);

   }

   for (int i = 0; i < n; i++)

   {

       in >> scores[i];

   }

   avg = (double)sum / n;

   cout << "A total number of " << n << " scores were processed " << endl;

   cout << "The sum of these scores is: " << avg << endl;

   cout << "The average of these scores is: " << avg << endl;

   sort(scores, n);

   cout << "The individual scores processed were: " << endl;

   char grade;

   for (int i = 0; i < n; i++){

       grade = calGrade(scores[i]);

       if (grade == 'F')

           cout << " * ";

       cout << scores[i] << " " << grade << endl;

   }

   out.close();

   cin.get();

   return 0;

}

char calGrade(double score){

   if (score >= 90 && score < 100)

       return 'A';

   else if (score >= 80 && score < 90)

       return 'B';

   else if (score >= 70 && score < 80)

       return 'C';

   else if (score >= 60 && score < 70)

       return 'D';

   else

       return 'F';

}

void sort(double grades[], int size){

   int i, j;

   double temp;

   for (i = 0; i < size; i++)

   {

       for (j = i + 1; j < size; j++)

           if (grades[i]>grades[j])

           {

               temp = grades[i];

               grades[j] = temp;

           }

   }

}

This is the error:

Error 1 error C4700: uninitialized local variable 'n' used f:\compsci235\final programm\final programm\final programm.cpp 34 1 Final Programm

Please advise on my mistake thanks.

Answer 1

#include <iostream>

#include <fstream>

#include <string>

#include <algorithm>

#include <vector>

using namespace std;

void sort(double grades[], int size);

char calGrade(double);

int main()

{

   int n = 0;

   double avg, sum = 0;;

   string in_file, out_file;

   cout << "Please enter the name of the input file: ";

   cin >> in_file;

   cout << "Please enter the name of the output file: ";

   cin >> out_file;

   ofstream out;

   out.open(out_file.c_str());

   // vector<double> scores;

   ifstream in1;

   in1.open(in_file.c_str());

   if (in1.fail())

   {

       cout << "Unable to open file" << endl;

       exit(0);

   }

    // calculate the number of entries in file

    // loop untill file ends

    while( !in1.eof() )

   {

        int temp;

        in1>>temp;

        n++;

   }

   double *scores = new double[n];

  

    // open file in read mode

    ifstream in(in_file.c_str());

    int index = 0;

    // loop untill file ends

    while( !in.eof() )

   {

        in>>scores[index];

       

        sum += scores[index];

       

        index++;

   }

   avg = (double)sum / (double)n;

   cout << "A total number of " << n << " scores were processed " << endl;

   cout << "The sum of these scores is: " << sum << endl;

   cout << "The average of these scores is: " << avg << endl;

   sort(scores, n);

   cout << "The individual scores processed were: " << endl;

   char grade;

   for (int i = 0; i < n; i++){

       grade = calGrade(scores[i]);

       if (grade == 'F')

           cout << " * ";

       cout << scores[i] << " " << grade << endl;

   }

   out.close();

   cin.get();

   return 0;

}

char calGrade(double score){

   if (score >= 90 && score < 100)

       return 'A';

   else if (score >= 80 && score < 90)

       return 'B';

   else if (score >= 70 && score < 80)

       return 'C';

   else if (score >= 60 && score < 70)

       return 'D';

   else

       return 'F';

}

void sort(double grades[], int N)

{

    int i, j;

  

    for (i = 0; i < N - 1; i++)

    {

        // the previous i elements are placed

        for (j = 0; j < N - i - 1; j++)

        {

            // swap the two elements

            if (grades[j] > grades[j+1])

            {

                int temp = grades[j];

                grades[j] = grades[j + 1];

                grades[j + 1] = temp;

            }

        }

    }

}

------------------------input.txt-------------------------

45
89
94
76
95
74
78

Sample Output

lease enter the name of the input file input.txt Please enter the name of the output file:output.txt A total number of 7 scores were processed The sum of these scores is: 551 The average of these scores is 78.7143 The individual scores processed were * 45 F 74 C 76 C 78 C 89 B 94 A 95 A