Modify your program from Exercise 1 so that it reads the information from the gr
ID: 3677877 • Letter: M
Question
Modify your program from Exercise 1 so that it reads the information from the gradfile.txt file, reading until the end of file is encountered. You will need to first retrieve this file from the Lab 7 folder and place it in the same folder as your C++ source code. Run the program.
I have the following code, but my data file is not being read. Please help! The values in the datafile are
90
45
73
21
62
// This program will read in a group of test scores( positive integers from 1 to 100)
// from the keyboard and then calculates and outputs the average score
// as well as the highest and lowest score. There will be a maximum of 100 scores.
#include <iostream>
#include <fstream>
using namespace std;
typedef int GradeType[100]; // declares a new data type:
// an integer array of 100 elements
float findAverage(const GradeType, int); // finds average of all grades
int findHighest(const GradeType, int); // finds highest of all grades
int findLowest(const GradeType, int); // finds lowest of all grades
int main()
{
GradeType grades; // the array holding the grades.
int numberOfGrades; // the number of grades read.
int pos; // index to the array.
float avgOfGrades; // contains the average of the grades.
int highestGrade; // contains the highest grade.
int lowestGrade; // contains the lowest grade.
ifstream dataFile;
dataFile.open("gradfile.txt");
if (! dataFile)
{
cout << "Error: Can't open the file named gradfile.txt. ";
exit(1);
}
// Read in the values into the array
pos = 0;
dataFile >> grades[pos];
while (grades[pos] != -99)
{
pos++;
dataFile >> grades[pos];
}
numberOfGrades = pos;
// call to the function to find average
avgOfGrades = findAverage(grades, numberOfGrades);
cout << endl << "The average of all the grades is " << avgOfGrades << endl;
highestGrade = findHighest(grades, numberOfGrades);
cout << endl << "The highest grade is " << highestGrade << endl;
lowestGrade = findLowest(grades, numberOfGrades);
cout << "The lowest grade is " << lowestGrade << endl;
system("pause");
return 0;
}
//****************************************************************************
// findAverage
//
// task: This function receives an array of integers and its size.
// It finds and returns the average of the numbers in the array
// data in: array of floating point numbers
// data returned: avarage of the numbers in the array
//
//****************************************************************************
float findAverage(const GradeType array, int size)
{
float sum = 0; // holds the sum of all the numbers
for (int pos = 0; pos < size; pos++)
sum = sum + array[pos];
return (sum / size); //returns the average
}
//****************************************************************************
// findHighest
//
// task: This function receives an array of integers and its size.
// It finds and returns the highest value of the numbers in
// the array
// data in: array of floating point numbers
// data returned: highest value of the numbers in the array
//
//****************************************************************************
int findHighest(const GradeType array, int size)
{
int highestgrade = array[0];
for (int pos = 0; pos < size; pos++)
if (array[pos] > highestgrade)
{
highestgrade = array[pos];
}
return highestgrade;
}
//****************************************************************************
// findLowest
//
// task: This function receives an array of integers and its size.
// It finds and returns the lowest value of the numbers in
// the array
// data in: array of floating point numbers
// data returned: lowest value of the numbers in the array
//
//****************************************************************************
int findLowest(const GradeType array, int size)
{
int lowestgrade = array[0];
for (int pos = 0; pos > size; pos++)
if (array[pos] < lowestgrade)
{
lowestgrade = array[pos];
}
return lowestgrade;
}
Explanation / Answer
#include <iostream>
#include <fstream>
using namespace std;
typedef int GradeType[100]; // declares a new data type:
// an integer array of 100 elements
float findAverage(const GradeType, int); // finds average of all grades
int findHighest(const GradeType, int); // finds highest of all grades
int findLowest(const GradeType, int); // finds lowest of all grades
int main()
{
GradeType grades; // the array holding the grades.
int numberOfGrades; // the number of grades read.
int pos; // index to the array.
float avgOfGrades; // contains the average of the grades.
int highestGrade; // contains the highest grade.
int lowestGrade; // contains the lowest grade.
fstream dataFile;
dataFile.open("gradfile.txt", ios::out | ios::app | ios::binary);
if (! dataFile)
{
cout << "Error: Can't open the file named gradfile.txt. ";
exit(1);
}
// Read in the values into the array
pos = 0;
dataFile >> grades[pos];
while (grades[pos] != -99)
{
pos++;
dataFile >> grades[pos];
}
numberOfGrades = pos;
// call to the function to find average
avgOfGrades = findAverage(grades, numberOfGrades);
cout << endl << "The average of all the grades is " << avgOfGrades << endl;
highestGrade = findHighest(grades, numberOfGrades);
cout << endl << "The highest grade is " << highestGrade << endl;
lowestGrade = findLowest(grades, numberOfGrades);
cout << "The lowest grade is " << lowestGrade << endl;
system("pause");
return 0;
}
//****************************************************************************
// findAverage
//
// task: This function receives an array of integers and its size.
// It finds and returns the average of the numbers in the array
// data in: array of floating point numbers
// data returned: avarage of the numbers in the array
//
//****************************************************************************
float findAverage(const GradeType array, int size)
{
float sum = 0; // holds the sum of all the numbers
for (int pos = 0; pos < size; pos++)
sum = sum + array[pos];
return (sum / size); //returns the average
}
//****************************************************************************
// findHighest
//
// task: This function receives an array of integers and its size.
// It finds and returns the highest value of the numbers in
// the array
// data in: array of floating point numbers
// data returned: highest value of the numbers in the array
//
//****************************************************************************
int findHighest(const GradeType array, int size)
{
int highestgrade = array[0];
for (int pos = 0; pos < size; pos++)
if (array[pos] > highestgrade)
{
highestgrade = array[pos];
}
return highestgrade;
}
//****************************************************************************
// findLowest
//
// task: This function receives an array of integers and its size.
// It finds and returns the lowest value of the numbers in
// the array
// data in: array of floating point numbers
// data returned: lowest value of the numbers in the array
//
//****************************************************************************
int findLowest(const GradeType array, int size)
{
int lowestgrade = array[0];
for (int pos = 0; pos > size; pos++)
if (array[pos] < lowestgrade)
{
lowestgrade = array[pos];
}
return lowestgrade;
}
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